Corals & Sea Anemones case method: 50 questions

In July, the owner replaced the lighting on a 90 cm SPS tank with a high-output LED and set it to the manufacturer's recommended maximum. A week later, the branch tips of the Acropora on the upper rockwork look whitish and translucent, the color has faded, and the polyps barely extend. Water temperature is 26°C, specific gravity 1.024, KH 8, all normal. The LPS on the lower level are open as usual.

What should be done first to stop the bleaching?

1. Extend the photoperiod by another 2 hours to help photosynthesis and watch
2. Add double the dose of supplements to provide nutrients and wait for the color to return
3. Reduce light output by 20–30%, keep the temperature stable, do a 10–20% water change, and observe for several days
4. Remove and discard the bleached Acropora immediately to prevent spreading to others

AnswerC. Reduce light output by 20–30%, keep the temperature stable, do a 10–20% water change, and observe for several days

ExplanationOnly the upper SPS bleached, water parameters are normal, and it happened right after a sudden increase in lighting, so this is zooxanthellae expulsion from light stress. The correct response is to cut light output by 20–30%, keep things stable with a water change, and observe over several days. Extending the photoperiod worsens light stress. Doubling supplements causes sudden KH or Ca swings and adds separate damage. Bleaching is not infectious, so discarding is unnecessary; if tissue remains on the skeleton, it often recovers within a few weeks. If tissue starts peeling, however, RTN is possible, so consult a shop or an experienced keeper the same day.

IssuesThe new light was run at maximum output from the start, giving the corals no time to acclimate. The lighting change, a major environmental shift, was not recorded, which delayed identifying the cause of the bleaching.

ImprovementWhen replacing or upgrading lights, start at 30–40% output and raise it by 10% every 1–2 weeks. Record every setting change with date and values, and check polyp extension and color daily. Make it a habit to suspect the most recent change whenever something changes.

On a January morning, the owner found that about 3 cm of tissue had peeled from the base of a large Acropora in the SPS tank, exposing white skeleton, with a thin film along the boundary. Nothing was wrong the night before. Yesterday a water change was done in a cold room and the new saltwater was added without checking its temperature. The thermometer reads 24°C, 2°C lower than usual.

What should be done first in this situation?

1. Bring the temperature back to 25–27°C with the heater, break off healthy branch tips leaving at least 2 cm, give them an iodine-based dip, and move them to a separate tank
2. Apply glue to the exposed skeleton to stop the tissue from peeling
3. Remove the whole colony, rinse it in fresh water to remove the film, then put it back
4. Wait for natural healing and act in a few days if it is still progressing

AnswerA. Bring the temperature back to 25–27°C with the heater, break off healthy branch tips leaving at least 2 cm, give them an iodine-based dip, and move them to a separate tank

ExplanationTissue peeling from the base within hours with a film at the boundary is classic RTN (rapid tissue necrosis), most likely triggered by temperature shock during the water change. It progresses fast, so waiting is not an option: fix the low temperature that caused it, cut off still-healthy branch tips, dip them, and protect them in a separate tank. Glue does not stop progression and damages tissue further. Rinsing in fresh water kills the remaining tissue by osmotic shock. The remaining main colony usually cannot be saved, so securing healthy parts is the priority. In the main tank, do a water change and check temperature and KH; if it spreads to other colonies, consult a specialist shop the same day.

IssuesNew saltwater was added without matching its temperature, and the winter room temperature dropped the tank by 2°C. The owner did not know that RTN can destroy a colony in hours, or that early fragging is essential.

ImprovementMatch the temperature and specific gravity of new saltwater to the main tank before adding it. In winter, run two heaters and check a digital thermometer every morning. Keep frag cutters, an iodine-based dip, and an isolation container on hand, and write out a procedure for initial RTN response.

On an April night, one head of a hammer coral in a 60 cm tank has turned into a brown jelly-like mass with no tentacles out, and there is a rotten smell when the owner leans close to the water surface. The adjacent hammer coral is normal. Three days ago, while moving the rockwork, this head was scraped against the edge of a skeleton. Temperature 26°C, nitrate 5 ppm.

What is the most appropriate action to take that night?

1. Assume the smell is from algae and deal with it at tomorrow's water change
2. Squirt supplements directly onto the affected area with a pipette to nourish it
3. Leave the colony in place and move the neighboring hammer coral away to observe
4. Isolate the colony immediately, suction off the melted part with a pipette, cut back to healthy tissue, and dip

AnswerD. Isolate the colony immediately, suction off the melted part with a pipette, cut back to healthy tissue, and dip

ExplanationBrown jelly-like disintegration with a foul smell is brown jelly disease (acute tissue breakdown by protozoa and bacteria), which often starts from a physical wound. It is highly contagious and spreads to LPS in the same tank within days, so even at night, isolate on the spot, suction off the jelly, cut back to healthy tissue, and give an iodine-based dip. Leaving it until tomorrow lets it infect the neighbor. Supplements do not remove the cause. Just moving the neighbor away does not help, as the pathogen drifts through the water. Clean the pipette and cutters used and keep them away from other animals. If it keeps progressing after treatment, consult a specialist shop the same day.

IssuesThe LPS flesh was scraped while moving the rockwork, and the wounded coral was not watched afterward. A clear warning sign, the foul smell, was taken lightly, and the possibility of a fast-spreading infection was not considered.

ImprovementWhen changing the layout, remove LPS first and hold them by the skeleton only so the flesh is not damaged. Observe any injured coral daily for 3 days. Keep an isolation container, dip solution, and a dedicated pipette on hand, and make it a rule to treat any brown breakdown on LPS the same day.

In September, a sebae anemone in a 45 cm tank has had its mouth gaping wide for 2 days, with white internal organs visible. Its body has shrunk to half its usual size and the tentacles are short. The pair of clownfish still nestle in it. Last week, after feeding was increased, nitrate rose above 20 ppm, and no water change has been done yet.

What should be done first?

1. Push a large piece of fish directly into its mouth to perk it up
2. Test all water parameters, do a 10–20% water change if nitrate is high, and observe daily
3. An open mouth means it is full, so leave it alone
4. Peel the anemone off the rock and move it directly under the light

AnswerB. Test all water parameters, do a 10–20% water change if nitrate is high, and observe daily

ExplanationA mouth that stays open and a shrunken body for more than 2 days are classic signs of decline, with the rise in nitrate as the background cause. First test all parameters; if nitrate is high, improve it gradually with a water change, and record how the mouth closes and how the body inflates daily. Forcing food in leads to undigested food rotting inside, which can trigger melting. An open mouth is not a sign of fullness but of expulsion or weakness. Forcibly peeling the foot can tear it fatally, and sudden strong light adds stress. Once it starts melting, the mucus fouls the water and kills fish, so if shrinking continues and tentacles melt, consider isolation and consult a specialist shop the same day.

IssuesWater quality was not tested after feeding was increased, and the nitrate rise was left unaddressed. The open mouth was taken lightly and nothing was done for 2 days while the shrinking progressed. The owner did not know that an anemone's mouth is a key health indicator.

ImprovementAlways test nitrate in any week when feeding is changed. Record the anemone's mouth, tentacles, and foot daily. If the mouth stays open, test and change water the same day; keep a spare container and heater ready so it can be isolated if it begins to melt.

In November, the Acropora and Montipora in an SPS tank have gradually turned dull brown over a month, and the former blues and purples are almost gone. Polyps are out and they are growing. Three fish were added and feeding frequency was increased. Tests show nitrate 25 ppm, phosphate 0.3 ppm. The lighting has not changed.

What is the most appropriate response?

1. Add 3 times the recommended dose of a coloring supplement to restore color
2. Run the lights at maximum output to reduce the zooxanthellae
3. Reduce feeding and gradually lower nitrate and phosphate with water changes and skimmer adjustment
4. Dip all the SPS in an iodine-based solution

AnswerC. Reduce feeding and gradually lower nitrate and phosphate with water changes and skimmer adjustment

ExplanationHigh nutrients let zooxanthellae multiply, turning the corals dull brown. This is not disease but a result of the environment, so the correct response is to reduce feeding and lower nitrate and phosphate gradually over several weeks with water changes and stronger skimming. Overdosing supplements disturbs water quality and does not address the cause. Suddenly running lights at maximum expels zooxanthellae all at once and causes bleaching, which is more dangerous. It is not an infection, so dipping is unnecessary and only adds stress. Make the improvement gradual; a sharp drop in nutrients damages tissue. If color does not return in a few weeks, or bleaching or tissue loss appears, consult a specialist shop.

IssuesThe nutrient rise from adding fish and feeding more was not tracked by testing, and the change was overlooked for a month. The color change was mistaken for disease, and cause and remedy were not thought through separately.

ImprovementConsider the tank's processing capacity before adding livestock or feeding, and test nitrate and phosphate weekly afterward. Record targets of nitrate 2–10 ppm and phosphate 0.03–0.1 ppm, and adjust feeding and water changes when they are exceeded.

In February, in an SPS tank with rigorous nutrient control, the Acropora have turned a pale pastel color overall, the branch tips are white as if burned, and some tissue has become thin and translucent. Tests show nitrate 0 ppm, phosphate 0.00 ppm. Lighting is strong, and absorbent media and the skimmer are run hard. Feeding is only once a week.

What is the most appropriate response?

1. Remove the absorbent media and feed small amounts of coral food or amino acids until nitrate and phosphate are just barely detectable
2. Add more absorbent media and keep nutrients at zero
3. Increase the lighting so photosynthesis makes up the nutrients
4. Add double the dose of KH supplement to promote skeletal growth

AnswerA. Remove the absorbent media and feed small amounts of coral food or amino acids until nitrate and phosphate are just barely detectable

ExplanationWith nutrients at absolute zero and strong light, zooxanthellae cannot be sustained, causing pastel fading and thinning tissue at the branch tips. This is starvation from nutrient deficiency, so the correct response is to remove the absorbent media and bring nitrate and phosphate back to detectable levels with small feedings. More absorbent media makes it worse. Stronger light reduces zooxanthellae further. Doubling KH does not fix the nutrient shortage, and a sudden KH spike causes tissue loss. Make the change gradually over several weeks; if tissue loss begins, consult a specialist shop the same day. The goal is low and stable nutrients, not zero.

IssuesThe idea that low nutrients are good was taken to the extreme, without knowing the danger of a zero state. Low feeding combined with strong lighting starved the corals. Readings below the detection limit were not recognized as abnormal.

ImprovementRecord a target range of nitrate 2–10 ppm and phosphate 0.03–0.1 ppm; if readings stay at zero, reduce absorbent media and increase feeding. Keep the balance between light and nutrients in mind, and change only one thing at a time.

In May, in a 90 cm tank where the SPS population has grown, the Acropora branch tips have not extended for 2 weeks and the white growth tips have disappeared. Some LPS skeletons look thin. A long-overdue test shows KH 5.5 dKH, Ca 380 ppm, Mg 1150 ppm, a big drop from the previous 8 dKH and 430 ppm. No supplements have been added for a while.

What is the most appropriate response?

1. Add a large amount of KH supplement at once to get back to 8 dKH today
2. Do a water change with tap water to dilute and reset the numbers
3. Supplements are dangerous, so add none and wait for natural recovery
4. Correct with supplements over several days at no more than 1 dKH per day, adjust Mg and Ca at the same time, and resume weekly testing

AnswerD. Correct with supplements over several days at no more than 1 dKH per day, adjust Mg and Ca at the same time, and resume weekly testing

ExplanationKH, Ca, and Mg are consumed in building coral skeletons, and consumption rises as colonies multiply. Neglected dosing let levels drop and growth stopped. Correct gradually at no more than 1 dKH per day over several days, and adjust Mg at the same time, since low Mg keeps KH and Ca from stabilizing. A large single dose causes tissue loss from the sudden KH swing and clouds the water with calcium carbonate precipitation. Tap water contains chlorine and heavy metals harmful to corals, and the change would also throw off specific gravity. There is no natural recovery; left alone, skeletons become brittle and tissue loss follows. After correction, make weekly testing a habit, and if tissue loss appears, consult a specialist shop the same day.

IssuesTesting and dosing were neglected even as corals multiplied, so the change in consumption went unnoticed. The owner lacked knowledge that sudden KH swings cause tissue loss, and was in a position to make the mistake of a large single dose.

ImprovementTest and record KH, Ca, and Mg weekly and set dosing by consumption. A dosing pump or two-part supplement added in small daily amounts keeps levels stable. Post a table with targets of KH 7–9 dKH, Ca 400–450 ppm, and Mg 1250–1350 ppm.

In June, a bubble-tip anemone in a 60 cm tank, 2 weeks after introduction, shrinks small in the morning, inflates by midday, and occasionally expels brown stringy matter from its mouth. At night the tentacles extend long and the color is good. The foot is firmly attached to the rock and it does not move. Temperature 26°C, nitrate 5 ppm. The owner worries it is sick.

What is the most appropriate response?

1. This is early decline, so move it to an isolation container immediately
2. This is normal contraction and waste expulsion in a healthy anemone, so keep observing while recording water quality and the foot's condition
3. Turn off the lights while it is shrunk to avoid stimulating it
4. Feed it daily to stop the stringy matter coming from the mouth

AnswerB. This is normal contraction and waste expulsion in a healthy anemone, so keep observing while recording water quality and the foot's condition

ExplanationAnemones contract periodically to exchange old water and expel brown stringy waste from the mouth. If the foot is firmly attached, it does not move, and the tentacles extend with good color at night, it is healthy; this is one of the few situations where watching is the right call. Isolation is a major stress from environmental change. Turning off the lights reduces photosynthesis and invites decline. Daily feeding causes indigestion and water fouling. However, if it stays shrunk, the mouth stays open, tentacles melt, or the foot detaches, those are signs of decline: test and change water that day.

IssuesThe owner could not tell healthy contraction from decline and nearly overreacted. Not knowing an anemone's normal behavior can lead to needless isolation or moves that truly weaken it.

ImprovementWrite out health criteria: foot attachment, mouth closure, tentacle extension at night, color, and whether it moves. Photograph it at the same time daily, and define abnormal as several signs appearing together. Keep records especially closely for the first month after introduction.

In October, in a 45 cm soft coral tank, a large toadstool leather has not extended its polyps for a week, a thin transparent film covers the surface, and the edges are starting to peel. There is no rotten smell and the flesh is firm. The other soft corals are normal. Temperature 25°C, nitrate 10 ppm, specific gravity 1.024.

What is the most appropriate response?

1. Peel the film off with tweezers to force the polyps out
2. It is starting to rot, so discard the colony right away
3. It is most likely a soft coral shedding, so do not touch it; direct flow at it and observe while keeping water quality stable
4. Move it directly under the light to acclimate it to strong light

AnswerC. It is most likely a soft coral shedding, so do not touch it; direct flow at it and observe while keeping water quality stable

ExplanationSoft corals such as toadstool leathers close for a few days to a week and shed a thin film to clear algae and mucus from their surface. With no foul smell and firm flesh, this is normal: just direct flow at it to help the film come off, keep water quality stable, and observe. Forcing the film off damages tissue and opens the door to infection. Discarding with no rot smell or breakdown is premature. A sudden lighting change adds stress and prolongs the shed. However, if it stays closed for more than 2 weeks, smells foul, or the flesh turns soft and breaks down, it is starting to melt: isolate it and consult a specialist shop the same day.

IssuesThe owner did not know that shedding is normal soft coral behavior and mistook it for disease. There were no criteria for judging the line between normal and abnormal (smell, flesh firmness, duration).

ImprovementSet a rule that a closed soft coral gets 1–2 weeks of stable water quality and flow before any action. Write out the abnormal criteria (foul smell, flesh breakdown, more than 2 weeks) and do not touch it otherwise. Compare progress with photos.

In March, tissue on a plating Montipora has been slowly turning white from the edge over 3 days, with the exposed skeleton spreading about 1 cm a day. It is not rapid but does not stop. Last week the owner rechecked specific gravity, found it low at 1.021, and hurriedly added concentrated saltwater to bring it back to 1.025. The other SPS are normal.

What is the most appropriate response?

1. Cut at least 2 cm on the healthy side of the advancing boundary to make frags, dip them, and let them recover elsewhere
2. Scrub the exposed skeleton with a toothbrush to prevent algae
3. Bring specific gravity back down to 1.021 to match the previous environment
4. Remove the whole colony, wipe off the water with a dry cloth, leave it a few minutes, then return it

AnswerA. Cut at least 2 cm on the healthy side of the advancing boundary to make frags, dip them, and let them recover elsewhere

ExplanationSlow tissue loss from the edge is STN (slow tissue necrosis), likely triggered by the osmotic stress of moving specific gravity 0.004 at once. STN spreads across the whole colony over days to weeks, so the reliable approach is to cut at least 2 cm on the healthy side of the advancing edge, give an iodine-based dip, and let the frags recover elsewhere. Scrubbing with a toothbrush does not stop progression and damages tissue further. Dropping specific gravity sharply again is a second shock. Leaving it in air for minutes dries the tissue and is fatal. Specific gravity corrections should be gradual, about 0.001 per day; if progression does not stop, consult a specialist shop the same day.

IssuesThe drop in specific gravity from evaporation was noticed late, and then the correction was rushed, causing osmotic shock. The owner did not understand the danger of sudden changes and focused only on getting the number back.

ImprovementTest specific gravity weekly and use an auto top-off with RO water to prevent drift from evaporation. Make corrections over several days at no more than 0.001 per day. Keep fragging tools and dip solution on hand for early STN response, and photograph the advancing edge daily to gauge its speed.

In August, a carpet anemone ordered online arrived nearly pure white in the bag with short tentacles. It was brown in the shop's photo. Shipping took 2 days and the bag water is lukewarm. The home tank is 60 cm with fairly strong lighting, 26°C, nitrate 5 ppm, and the other corals are thriving. A clownfish is waiting to move in.

What is the most appropriate way to introduce it?

1. Place it on a rock directly under the light right away so strong light restores the zooxanthellae
2. Float the bag in the tank, release it after 10 minutes, and house it with the clownfish
3. White means a defective animal, so refuse delivery and send it straight back
4. Acclimate for at least 30 minutes, place it in a dimly lit spot, increase light gradually over several weeks, and wait for recovery with small feedings

AnswerD. Acclimate for at least 30 minutes, place it in a dimly lit spot, increase light gradually over several weeks, and wait for recovery with small feedings

ExplanationAn animal bleached by losing its zooxanthellae from heat and darkness in transit is weak, and strong light often causes it to melt from light damage. Acclimate for at least 30 minutes to the water, start in a dimly lit spot and raise light gradually over several weeks, and feed small amounts 1–2 times a week while the zooxanthellae recover. Direct strong light can be fatal. A short acclimation causes osmotic shock. Even a bleached animal can recover if the mouth is closed and the foot attaches, so check its condition before refusing delivery. If it is melting and breaking down, however, do not put it in the tank; send photos to the shop and consult them.

IssuesThe owner bought in midsummer without considering the risk of long transit, and did not know how to introduce a bleached animal. Eagerness to house the clownfish quickly could have led to decisions that burdened the weakened animal.

ImprovementIn midsummer and midwinter, choose a shop with short transit or pick up in person. Make at least 30 minutes of acclimation and gradual light acclimation from low light the standard procedure. Photograph the animal on arrival to document its condition, and contact the shop early if anything is wrong.

In December, the flesh edge of a lobo coral placed on the sand bed has receded over a few days and the skeleton is beginning to show. After the flow pump was turned up, sand has often been kicked up and settled on the coral's edge. A hermit crab is often seen walking over it. Water quality is fine: 26°C, KH 8, nitrate 8 ppm.

What is the most appropriate response?

1. Push sand against the flesh edge with tweezers to hold it in place
2. Move it to a rock ledge or low stand where sand cannot reach it, redirect the flow to stop sand being kicked up, and dip the receding part
3. Turn the flow pump up further to blow the sand away
4. It is melting, so soak the whole coral in iodine-based dip overnight

AnswerB. Move it to a rock ledge or low stand where sand cannot reach it, redirect the flow to stop sand being kicked up, and dip the receding part

ExplanationLPS such as lobo corals exhaust themselves producing mucus to shed sand that settles on their flesh, and if it goes on, the tissue recedes from the edge and infection sets in. The correct response is to move it to a rock ledge or stand out of the sand, redirect the flow so sand is no longer kicked up, and give the receding part a short dip to prevent infection. Pushing sand in is counterproductive. More flow kicks up more sand and constantly abrades the flesh. An overnight dip is far too long and damages the coral itself. If the hermit crab climbs on it often, rethink the placement. If the recession does not stop within days and turns brown and mushy, it may be turning into brown jelly disease: isolate it and consult a specialist shop the same day.

IssuesThe side effect of sand being kicked up after changing the flow was not considered, and sand was left piling on the coral. The owner lacked knowledge that LPS are sensitive to sand and physical irritation, and overlooked the hermit crab trampling it.

ImprovementAfter changing flow, watch sand movement and coral edges for a few days. Put LPS kept on sand on a low stand high enough that sand does not pile on the edges. If hermit crabs or snails climb on them, reduce their numbers or change the layout. Check edge recession with daily photos and act early.

On an April morning, a bubble-tip anemone in a 60 cm tank had moved during the night and half its body was sucked into the unguarded intake of a flow pump. Tentacles are visible inside the intake and the rest of the body is shrunk outside. The water is slightly cloudy and the clownfish swim anxiously around it. The pump is still running.

What should be done first?

1. Pull the outer body free with the pump still running
2. Set the pump to maximum to push it back out from the outlet side
3. Cut power to the pump immediately, disassemble the pump to free the body without pulling, collect any torn tissue, and do a water change
4. Wait for it to work itself free and check again in the evening

AnswerC. Cut power to the pump immediately, disassemble the pump to free the body without pulling, collect any torn tissue, and do a water change

ExplanationPump intakes are the most common anemone accident, and pulling while the pump runs tears the body fatally. First cut power to the pump, then disassemble it to free the body without injury. Torn tissue fouls the water and releases toxins, so collect it, and do a water change if the water is cloudy. Pushing back from the outlet side damages the body inside. Waiting lets the suction continue and shred the tissue. After freeing it, place it in a quiet spot in the shade of a rock and observe for several days to see whether it regenerates. If it stays shrunk with the mouth open and begins to melt, isolate it and consult a specialist shop the same day. Fit guards on all other pumps immediately.

IssuesThe owner knew anemones move at night but had no guard on the flow pump intake. There was no habit of checking its location daily, so the accident was found late.

ImprovementFit sponge or mesh guards on every intake, and check the anemone's position every morning and before bed. For an anemone that moves often, review flow and lighting and create a spot where it settles. Learn how to stop the pump and the disassembly procedure in advance.

In May, a large hermit crab climbed the rock and onto an Acropora, breaking off 2 branches that fell onto the sand. The broken branches are about 5 cm with tissue intact. The break points on the main colony still have tissue. Temperature 26°C, KH 8, water quality stable. The owner does not know what to do with the broken branches.

What is the most appropriate response?

1. Pick up the broken branches underwater without letting them dry, glue them to frag plugs, place them in fairly strong flow, and observe the break points on the main colony
2. The broken branches are useless, so discard them and apply glue to the break points on the main colony
3. Glue the broken branches back onto the main colony's break points as they were
4. Take the branches out, rinse the sand off under tap water, and put them back

AnswerA. Pick up the broken branches underwater without letting them dry, glue them to frag plugs, place them in fairly strong flow, and observe the break points on the main colony

ExplanationA broken SPS branch grows as a frag as long as tissue remains. Pick up the branches underwater, glue them to frag plugs without air exposure, and place them where fairly strong flow washes mucus away. The break points on the main colony normally heal on their own, so glue is unnecessary; observation is enough. Reattaching the branches does not fuse the skeletons, and the glued surface damages tissue and opens the door to infection. Tap water kills tissue with chlorine and osmotic shock. Observe the break points and sand-contact areas for several days, and dip if they start turning white and receding. Review the species and size of the hermit crab that caused it, and remove any that climb on corals.

IssuesA large hermit crab was introduced without considering the risk of it walking over SPS and breaking branches. Corals were placed on the rockwork without thinking about the paths of bottom-dwelling animals.

ImprovementLimit hermit crabs and snails to small species, and remove any that climb on corals. Secure SPS firmly to the rock with glue or putty. Keep frag plugs and coral glue on hand so breaks can be fragged immediately.

On a July evening, the owner came home to find part of the live rock had collapsed, and the staghorn Acropora on top had fallen onto an LPS torch coral and the two are touching. The torch coral's tentacles are wrapped around the Acropora's branches, and the contact area on the Acropora is beginning to turn white. Other rocks also look unsteady.

What should be done first?

1. Leave it overnight and rebuild the rockwork on tomorrow's day off
2. Scrub the contact area with a toothbrush to remove the mucus
3. Lift only the Acropora out, check the damage in the air, and put it back
4. Immediately separate the two underwater, dip the damaged parts and secure them in a stable position, and fix the collapsed rocks with glue or putty

AnswerD. Immediately separate the two underwater, dip the damaged parts and secure them in a stable position, and fix the collapsed rocks with glue or putty

ExplanationLPS dissolve SPS tissue within hours with their tentacles and stinging cells, so leaving the contact overnight can lead to RTN starting from the contact point. Separate the two underwater immediately, prevent infection on the damaged parts with an iodine-based dip, and secure them in a stable spot. Fix the collapsed rocks with glue or putty so they cannot fall again. A toothbrush scrapes off remaining tissue. Taking it into the air dries the tissue, and SPS are especially sensitive to air exposure. Waiting until tomorrow is wrong because the LPS attack continues. After securing, observe the contact area for bleaching or tissue loss for several days; if it progresses, frag the healthy parts and consult a specialist shop.

IssuesThe live rock was simply stacked without being secured, in a structure that could collapse from hermit crab or snail movement. SPS and LPS were not spaced far enough apart, in a layout where a collapse put them in contact.

ImprovementSecure the rockwork with glue, putty, or acrylic rods and confirm it does not move when shaken. Keep SPS and LPS at least 10 cm apart in a layout where they cannot touch even if something falls. Check rock stability before going out, and make a habit of looking over the whole tank on returning home.

In September, one side of a birdsnest coral placed 5 cm from a Galaxea has been turning white and melting over several days. Nothing touches it during the day, but after lights-out at night, long transparent tentacles can be seen extending from the Galaxea and reaching the birdsnest. Water quality is normal.

What is the most appropriate response?

1. Galaxea are aggressive, so remove it from the tank
2. Move the birdsnest at least 15 cm away, beyond the reach of the sweeper tentacles, and dip the damaged part
3. Keep the lights on at night so the sweeper tentacles do not come out
4. Cut the Galaxea's tentacles with scissors

AnswerB. Move the birdsnest at least 15 cm away, beyond the reach of the sweeper tentacles, and dip the damaged part

ExplanationGalaxea extend long sweeper tentacles at night that sting and dissolve neighboring corals, reaching especially far downstream of the flow. The correct response is to move the damaged birdsnest at least 15 cm away, beyond the tentacles' reach, and dip the damaged part to prevent infection. Removal is unnecessary; this is a placement problem. Nighttime lighting disrupts the corals' physiological rhythm and causes bleaching and decline. Cut tentacles regenerate quickly and the cut becomes an entry point for infection. After relocating, check the tentacles' reach with a flashlight at night for several days, and frag the healthy parts if the damaged area spreads.

IssuesNot knowing it was a highly aggressive species, the owner placed it without considering the reach of its sweeper tentacles. Looking at the tank only during the day delayed noticing the nighttime attacks.

ImprovementBefore introducing a coral, research each species' aggressiveness and sweeper tentacle length; keep aggressive species at least 15 cm away and never upstream of others. Check the tentacles with a flashlight after lights-out. Make a layout map and check for interference before placing any new coral.

In June, a long-tentacle anemone had worked its way deep into the rock, so the owner pried its foot off with a spatula to move it. Part of the foot remained on the rock, and thin tissue protrudes from the tear. The body is tightly shrunk and the mouth is open. The tank is 60 cm, 26°C, nitrate 5 ppm.

What is the most appropriate action to take next?

1. Seal the tear with glue and secure it back on the original rock
2. Place it in strong light directly under the lamp to speed recovery
3. Place it in a quiet, moderate-flow spot in the shade of a rock, keep water quality stable without touching it, and check daily for an open mouth or melting
4. Move it to a separate tank right away and feed it daily to build its strength

AnswerC. Place it in a quiet, moderate-flow spot in the shade of a rock, keep water quality stable without touching it, and check daily for an open mouth or melting

ExplanationAn anemone's foot can regenerate, but right after a tear the risk of infection and melting is high. The keys to recovery are rest and stable water quality: place it in a moderate-flow spot in the shade of a rock, do not touch it, and observe daily. Glue damages tissue and is toxic. Strong light adds stress, and a weakened body melts from light damage. Moving to another tank piles on more stress, and feeding when it cannot digest hastens decline. If it keeps shrinking with the mouth open and the tentacles melt and release mucus, isolate it to protect the main tank and consult a specialist shop the same day. When a foot must be detached, use ice or stronger flow and wait for it to let go on its own.

IssuesThe owner forcibly pried the anemone's foot off with a tool and tore it. They did not know the safe ways to move one (bringing ice near it, encouraging it with flow, moving the whole rock).

ImprovementTo move an anemone, move the whole rock, or bring ice near it and wait for it to release its foot by itself. Reduce crevices it can crawl into and prepare a spot it will like in advance. After a move, record the foot and mouth for several days to confirm recovery.

During an August water change, the owner cut a finger about 2 cm on the edge of a live rock. It bled, but thinking it was minor, they kept rearranging the layout in the tank and touched the corals and anemone bare-handed. Afterward they only rinsed lightly with water. The next day, the area around the cut is red, swollen, and painful.

What is the most appropriate response the next day?

1. Because of the risk of a marine bacterial infection, wash the wound with soap and running water and see a doctor, mentioning the aquarium work
2. The seawater should have disinfected it, so leave it alone
3. Warm the swollen area to improve circulation, apply an over-the-counter medication, and wait
4. Soak the wound in the tank's seawater to rinse it

AnswerA. Because of the risk of a marine bacterial infection, wash the wound with soap and running water and see a doctor, mentioning the aquarium work

ExplanationMarine aquariums harbor bacteria such as Vibrio and Mycobacterium that infect through wounds. Redness, swelling, and pain after putting a cut hand in seawater are early signs of infection: wash with soap and running water and see a doctor, mentioning the aquarium work and seawater contact. People with diabetes or liver disease are especially prone to severe illness. Seawater is not sterile and does not disinfect. Warming spreads the inflammation, and waiting with over-the-counter medication delays care. Soaking in seawater again adds more bacteria. If a slow-healing lump or ulcer persists for weeks, mycobacterial infection is possible, so always tell the doctor about the aquarium.

IssuesThe owner put a wounded hand in the tank and touched cnidarians bare-handed. They lacked knowledge of the bacterial infection risk of marine aquariums and of first aid for people.

ImprovementNever put a wounded hand in the tank. Always wear gloves that cover to the elbow and wash hands with soap afterward. If you get a cut, stop work and rinse under running water. Do not wait until the next day for swelling or pain; see a doctor.

In March, while cleaning the glass, the owner's arm knocked an Acanthastrea off its stand onto the sand. The skeleton split in two; on one piece the flesh is torn and the skeleton is exposed, while the other is unharmed. Temperature 26°C, KH 8, water quality good. The owner is unsure whether to discard the damaged piece.

What is the most appropriate response?

1. Glue both pieces back together as they were
2. The piece with torn flesh cannot be saved, so discard it and return only the intact piece
3. Take the whole thing out, rinse off the sand under tap water, and return it to the stand
4. Gently rinse the sand off both pieces underwater, dip the torn piece and place it in gentle flow, and observe for several days

AnswerD. Gently rinse the sand off both pieces underwater, dip the torn piece and place it in gentle flow, and observe for several days

ExplanationLPS such as Acanthastrea often regenerate even with a split skeleton as long as a mouth and flesh remain. Gently rinse the sand off underwater, give the torn piece an iodine-based dip to prevent infection, place it in gentle flow that does not strain the flesh, and observe for several days. Gluing the split skeleton back together does not fuse it, and glue touching the flesh damages it. Discarding while flesh remains is premature. Tap water kills tissue with chlorine and osmotic shock. If during observation the torn part turns brown and mushy and smells foul, brown jelly disease is possible: isolate immediately, cut away the affected part, and consult a specialist shop the same day.

IssuesThe coral was placed on a stand where arm movement during cleaning could knock it off, and it was not secured. The owner did not know about the regenerative ability of LPS or how to handle skeletal damage.

ImprovementSecure LPS to stands or rocks with glue or putty and keep them away from the glass. Check the path of your arm before cleaning. Keep dip solution and a gentle-flow recovery spot ready; if one falls, first rinse the sand off underwater and record the tissue's condition with daily photos.

In October, a sebae anemone was added to a 90 cm tank housing a carpet anemone. The next morning, the sebae had moved near the carpet, the tentacles that touched have melted and shrunk, and its mouth is open. The carpet is unharmed with its tentacles extended long. Water quality is stable.

What is the most appropriate response?

1. Keep both in the same spot and let the weaker one get used to the stronger
2. Move the sebae, rock and all, to a distant spot, use a divider or flow adjustment to prevent re-contact, and observe the wound's recovery
3. Move the carpet anemone to a separate tank to isolate it
4. Cut off the melted tentacles to prevent infection

AnswerB. Move the sebae, rock and all, to a distant spot, use a divider or flow adjustment to prevent re-contact, and observe the wound's recovery

ExplanationAnemones attack each other with stinging cells, and carpet anemones in particular have potent venom that dissolves other anemones. Move the weaker sebae, rock and all, far away, use a divider or adjust flow so it cannot walk back, and observe the wound's recovery. They never get used to each other; re-contact means melting. The carpet is unharmed, and isolating it would weaken both through environmental change. Cutting tentacles adds tears that become entry points for infection and melting. If the sebae's shrinking and open mouth continue for days, recheck water quality; if it starts melting, isolate it to protect the main tank and consult a specialist shop. Keeping multiple anemone species in one tank is inherently high-risk.

IssuesThe owner lacked knowledge that multiple anemone species in one tank attack each other with stinging cells. They also did not account for anemones walking, and the layout did not prevent contact.

ImprovementKeep one anemone species per tank as a rule; if keeping several, provide ample distance and dividers. Check positions every morning after introduction and move one, rock and all, as soon as they approach. Research each species' stinging strength and compatibility before introducing it.

In February, the owner peeled a newly purchased Acropora frag off its plug to glue it directly to the rock, and the tissue at the base tore, exposing a few millimeters of skeleton. It was out of the water for about 30 seconds during the work. The frag is 3 cm, and the tissue and color at the branch tip are good. Temperature 26°C, KH 8.

What is the most appropriate response?

1. Give a short iodine-based dip underwater, secure it to the rock without glue touching the exposed area, place it in fairly strong flow, and observe for several days
2. Apply a thick layer of glue over the exposed area to protect it and secure it directly under the light
3. Take it out of the water again, wipe the wound with a tissue, and put it back
4. Keep it in an isolation container until the wound heals and feed it daily

AnswerA. Give a short iodine-based dip underwater, secure it to the rock without glue touching the exposed area, place it in fairly strong flow, and observe for several days

ExplanationA few millimeters of damage at the base of an SPS is usually covered by tissue within weeks if infection is prevented. Give a short iodine-based dip underwater, secure it to the rock so no glue touches the exposed area, place it where fairly strong flow washes mucus away, and observe for several days. A thick layer of glue blocks tissue regrowth, and placement directly under strong light stresses the weakened tissue. Taking it out and wiping with a tissue strips tissue, and air exposure itself is a heavy burden on SPS. An isolation container has unstable water quality and flow, and SPS need a stable environment more than food. If the damage spreads and recedes white, STN is possible, so secure the healthy parts and consult a specialist shop that day.

IssuesA frag that did not need removing was forcibly peeled off its plug, tearing the tissue. The length of air exposure during the work was not considered either. The owner did not know the basics of frag handling.

ImprovementGlue frags to the rock plug and all; if the plug must go, trim it small with cutters and leave the rest. Work underwater and keep air exposure to a minimum. Prepare iodine-based dip and glue before working, and learn mounting methods that do not touch the tissue.

In November, while cleaning algae off the glass with a magnet cleaner, the owner scraped hard across the tentacles and flesh of a hammer coral that was touching the glass. Pieces of tentacle tore off and are drifting in the water, and there is a tear in the flesh. The coral has shrunk. The pair of clownfish are unharmed.

What is the most appropriate response?

1. Leave the torn tentacles alone and just watch the coral
2. Press the torn flesh back into shape with a finger
3. Apply disinfectant directly to the wound in the flesh
4. Collect the drifting tissue with a net, move the coral away from the glass, give it a short dip, and observe for several days

AnswerD. Collect the drifting tissue with a net, move the coral away from the glass, give it a short dip, and observe for several days

ExplanationTorn tissue rots, fouls the water, and becomes a source of infection for other corals, so collect it with a net. Move the injured coral to a stable spot away from the glass, give a short iodine-based dip to prevent infection, and watch for several days for the tear spreading or any foul smell. Leaving it invites infection and water fouling. Pressing with a finger does not restore tissue and damages it further. Applying disinfectant directly kills the tissue. LPS can progress from a wound to brown jelly disease, so if mushy breakdown or a foul smell appears, isolate immediately, cut away the affected part, and consult a specialist shop the same day.

IssuesThe coral was placed touching the glass and the path of the cleaning tool was not considered. There was no habit of checking nearby animals before working, and the owner was not aware that LPS flesh is sensitive to physical contact.

ImprovementPlace corals at least 5 cm from the glass. Before cleaning, check for animals in the tool's path and move them, rock and all, if needed. Move the magnet cleaner slowly while watching what it touches, and always inspect the animals afterward.

On a May morning, a bubble-tip anemone is missing from an overflow tank. Part of a tentacle is visible at the top of the standpipe, the pump in the sump sounds different, and the water is draining weakly. The clownfish swim restlessly and the water is slightly cloudy. The main pump is running.

What should be done first?

1. Pull the tentacle out from the top of the standpipe with the pump running
2. Give up on the anemone and turn the pump up to flush the blockage through the plumbing
3. Stop the main pump, check the standpipe and sump, remove the anemone without injuring it, and treat the cloudiness with a water change and activated carbon
4. Wait for tomorrow's day off and take the plumbing apart at leisure

AnswerC. Stop the main pump, check the standpipe and sump, remove the anemone without injuring it, and treat the cloudiness with a water change and activated carbon

ExplanationAnemones often get into overflow plumbing and sumps; pulling without stopping the pump tears the body, and if it is crushed and melts inside the pipe, toxic mucus circulates through the whole tank. First stop the main pump, check the standpipe and then the sump, and disconnect the plumbing to remove it without injury. The cloudiness is from tissue breakdown, so treat it with a water change and activated carbon and check the fish's breathing. Turning the pump up shreds the body and invites the worst outcome. Waiting until tomorrow lets it melt and endangers the whole tank. Observe the recovered anemone in a quiet spot and isolate it if melting progresses. A blocked pipe can also cause an overflow, so work quickly.

IssuesNo guard or netting was fitted to the top of the standpipe, and the anemone's tendency to wander was underestimated. The owner also had not considered that a blocked pipe could lead to a flood.

ImprovementFit netting or sponge guards to the top of the standpipe and all intakes. Check the anemone's position every morning, and review the environment for one that moves often. Learn in advance how to stop the pump and disassemble the plumbing, and keep saltwater ready for emergency water changes.

On a July morning, all the flow pumps in an SPS tank had been off all night because a plug had come out. There is an oily film on the surface, the SPS polyps are not out at all, and some are coated in mucus. The water is 28°C from the heat of the lights, and the fish are gasping near the surface. The pH measures low at 7.7.

What should be done first?

1. Remove all the mucus-covered SPS and dip them
2. Immediately restart flow and aeration, remove the surface film, lower the temperature, restore water quality with a water change, and then check each coral
3. Raise the pH to 8.3 at once with a supplement
4. Turn off the lights for several days to let the corals rest

AnswerB. Immediately restart flow and aeration, remove the surface film, lower the temperature, restore water quality with a water change, and then check each coral

ExplanationWith no flow, oxygen ran out, carbon dioxide built up and lowered the pH, and the surface film stopped gas exchange. The top priority is restoring flow and aeration; remove the film, lower the temperature, restore water quality with a water change, and then check each coral for mucus and tissue loss. The mucus is self-cleaning and usually washes off once flow returns. Dipping every coral adds needless stress. A sudden pH rise does more damage than the oxygen shortage, and raising it with a supplement is dangerous in itself. Days of darkness stop photosynthesis and hinder recovery. Frag the healthy parts of any coral whose tissue starts peeling, and if the fish's breathing does not improve, consult a specialist shop the same day.

IssuesThe pumps all depended on a single outlet, with no way to notice if it came out. There was no means of alerting to a stoppage, so the nighttime oxygen shortage and temperature rise were not found until morning.

ImprovementSecure power strips and split the pumps across multiple circuits. Set up a monitor that alerts to temperature and power loss, and keep a battery-powered air pump. Check the surface film and polyp extension every morning, and log pH and temperature to know the normal values.

On a January night, the owner came home to find the tank thermometer reading 31°C. The heater's thermostat apparently failed and stayed on. The Acropora look whitish with polyps retracted, the LPS are shrunk, and the anemone is shrunk with its mouth open. The fish are breathing rapidly near the surface. Room temperature is 18°C.

What should be done first?

1. Unplug the heater immediately, increase aeration, and lower the temperature gradually to 26°C at about 1°C per hour using ice packs or cooled saltwater
2. Add a large amount of ice to drop it to 25°C at once
3. Add cold tap water to lower temperature and specific gravity at the same time
4. Just lower the heater setting, leave it overnight, and check in the morning

AnswerA. Unplug the heater immediately, increase aeration, and lower the temperature gradually to 26°C at about 1°C per hour using ice packs or cooled saltwater

Explanation31°C is a danger zone where bleaching and tissue loss progress rapidly, and oxygen also runs short. First unplug the failed heater, secure oxygen with aeration, and lower the temperature gradually at about 1°C per hour by floating ice packs or adding cooled saltwater little by little. Dropping it at once with ice causes temperature shock and RTN. Tap water does double damage with chlorine and a drop in specific gravity. A failed thermostat will likely not stop even at a lower setting, and leaving it overnight means total loss. Keep watching for bleaching and tissue loss for several days afterward; frag the healthy parts of any coral with tissue loss and consult a specialist shop the same day. Replace the heater.

IssuesThe owner never anticipated a heater staying on after failure, and had no overheat safety device or temperature alert. The thermometer was only checked after getting home, so the problem was found late.

ImprovementPair the heater with an external thermostat and a safety cutoff for overheating. Install a monitor that alerts to abnormal temperature, and replace heaters every 1–2 years. Keep ice packs for emergency cooling and spare saltwater on hand.

On an August afternoon, the owner came home to find the aquarium chiller stopped with an error display and the water at 29.5°C. Room temperature is 33°C. The SPS polyps are retracted and some look whitish. The anemone is shrunk. The lights are on at full output. There is no spare chiller and repair will take several days.

What should be done first?

1. Turn off the lights, shut the room up, and wait until tomorrow
2. Add a large amount of ice directly to drop it to 25°C at once
3. Turn on the air conditioning to lower room temperature and simply wait for the chiller repair
4. Dim the lights, lower room temperature with air conditioning, bring the water gradually below 27°C with a cooling fan and frozen water bottles, and increase aeration

AnswerD. Dim the lights, lower room temperature with air conditioning, bring the water gradually below 27°C with a cooling fan and frozen water bottles, and increase aeration

ExplanationAbove 29°C is a danger zone where SPS bleaching and RTN begin, and oxygen drops. Reduce light output to cut its heat, lower room temperature with air conditioning, use a cooling fan for evaporative cooling, and float frozen water bottles to bring the water below 27°C at about 1°C per hour. Evaporation raises specific gravity, so remember to top off. Increase aeration to secure oxygen. Adding ice directly causes tissue loss from the sudden temperature change and drop in specific gravity. Air conditioning alone lowers water temperature too slowly; a fan is needed as well. Turning off the lights alone reduces heat but does not cool the water, and waiting until tomorrow risks total loss. Watch any bleached or peeling corals for several days, and if it progresses, frag the healthy parts and consult a specialist shop.

IssuesCooling in midsummer depended on a single chiller with no backup for a failure. There was no way to learn of a temperature problem while away, so it was found late.

ImprovementKeep a cooling fan permanently installed and frozen water bottles in the freezer as a backup for chiller failure. Set up a temperature monitor that sends alerts to a smartphone. Lower light output in midsummer, and clean and test the chiller in June.

On an April morning, the auto top-off sensor had malfunctioned because of algae and RO water had been pouring in all night. The sump water level rose to its limit and specific gravity is 1.019. The SPS are producing mucus, the LPS flesh is bloated and swollen, and the anemone is abnormally inflated. The fish are restless.

What should be done first?

1. Add concentrated saltwater all at once to get back to 1.025 today
2. Stop the top-off and raise specific gravity back over several days with water changes using slightly concentrated saltwater, at about 0.001–0.002 per day
3. Leave it alone and wait for evaporation to raise specific gravity naturally
4. Sprinkle salt mix directly into the tank and let it dissolve

AnswerB. Stop the top-off and raise specific gravity back over several days with water changes using slightly concentrated saltwater, at about 0.001–0.002 per day

ExplanationA sudden drop in specific gravity bloats tissue through osmotic shock and causes RTN in SPS and tissue loss in LPS. Adding concentrated saltwater all at once to animals already in shock is a second shock that spreads the damage, so stop the top-off and bring it back gradually over several days at about 0.001–0.002 per day with water changes using slightly concentrated saltwater. Waiting for evaporation leaves the low-salinity period too long for the tissue to survive. Adding salt mix directly creates local high concentrations that burn any tissue it touches. For several days, check each coral daily for mucus, tissue loss, and melting, and frag the healthy parts of any that progress. Clean the sensor and install a safety device that limits top-off volume.

IssuesThe auto top-off sensor was not cleaned, and there was no safety device limiting the volume added in case of malfunction. The owner did not understand that a sudden change in specific gravity causes osmotic shock.

ImprovementClean the auto top-off sensor weekly, and limit the reservoir to less than one night's volume or set a timer cap on top-off. Test specific gravity weekly, and set a procedure for correcting problems gradually at 0.001–0.002 per day.

On a June night, a dosing pump setting error injected a large amount of KH supplement at once. The whole tank is cloudy white, and KH measures 14 dKH against 8 dKH the day before. The SPS are producing mucus with polyps retracted, and white crystals appear to be deposited on parts of the skeleton. Temperature 26°C.

What should be done first?

1. Add a large amount of activated carbon to clear the cloudiness and wait until morning
2. Add an equal amount of Ca supplement to neutralize it
3. Stop the dosing pump, do several 10–20% water changes, bring KH back to 8–9 over several days, and watch for tissue loss
4. Drop KH at once with a pH reducer

AnswerC. Stop the dosing pump, do several 10–20% water changes, bring KH back to 8–9 over several days, and watch for tissue loss

ExplanationA sudden KH spike causes cloudiness from calcium carbonate precipitation and SPS tissue loss from abrupt osmotic and pH changes. First stop the dosing pump to prevent further injection, then do several 10–20% water changes and bring KH back to 8–9 dKH gradually over several days, not abruptly. Activated carbon does not remove precipitate or correct the underlying number. Adding Ca drives further precipitation and worsens the cloudiness. A pH reducer piles on another sudden change, a double shock. The precipitate can also clog pumps and filters, so clean them. Watch each SPS for tissue loss and mucus for several days; frag the healthy parts of any with RTN and consult a specialist shop.

IssuesThe dosing pump's output was not test-measured after the setting was changed, and there was no safety setting to stop over-injection. The owner did not recognize that a sudden large dose of supplement can cause RTN.

ImprovementAfter changing pump settings, always verify the actual output with a measuring cup. Set a daily injection cap, and divide supplements into 1–2 day containers to limit the damage if it runs wild. Test KH at least weekly; if the change is large, stop dosing and look for the cause.

On a September night after lights-out, a bubble-tip anemone had walked across the rock and settled with its foot spread over an Acropora colony. The tissue on the branches it touches is starting to turn white. The Acropora is on the upper level in strong flow, and the anemone had been moving repeatedly for several days looking for a place to settle.

What should be done first?

1. Encourage the anemone to release on its own with flow or by bringing ice near it, then move it rock and all to a distant spot, and dip the damaged SPS
2. Pry the anemone off with a spatula and press it onto another spot right away
3. The anemone has found a place it likes, so leave it there
4. Peel the Acropora off the rock to get it away from the anemone

AnswerA. Encourage the anemone to release on its own with flow or by bringing ice near it, then move it rock and all to a distant spot, and dip the damaged SPS

ExplanationAn anemone's stinging cells dissolve SPS tissue within hours, so leaving the contact means losing the Acropora. But prying the foot off with a tool tears it fatally, so direct flow at it or bring ice near it to make it release on its own, then move it rock and all far away. Prevent infection on the damaged SPS with an iodine-based dip, and frag the healthy parts if tissue loss spreads. Prying and pressing injures the anemone, and it will walk off again. Peeling the Acropora off the rock breaks a glued colony and damages tissue. An anemone that keeps moving is signaling dissatisfaction with flow or lighting, so creating a spot where it settles is the real fix. Check for contact and tissue loss again the next day, and consult a specialist shop if it progresses.

IssuesThe owner missed the sign that repeated movement meant the environment did not suit the anemone. The risk of keeping an anemone with SPS was underestimated, and there was no preparation for it walking onto them.

ImprovementAs a rule, keep anemones in a separate tank from SPS; if housed together, separate the rockwork by a distance it cannot walk. For one that keeps moving, reduce flow, adjust light intensity, and provide a rock crevice where it can settle. Check its position every night after lights-out.

In December, the owner put a hand in the tank for a water change and felt a tingling in the fingertips. There is no wound on the hand. One of the flow pumps has had a small crack since last week. Recently, polyp extension has been poor across the corals, and the anemone is unsettled and keeps moving.

What should be done first?

1. Assume it is a sting from stinging cells and continue working with gloves
2. It is just salt stinging a cut, so wash the hands and continue working
3. Unplug the power cord of the tingling pump with wet hands
4. Pull the hand out immediately, cut power to the equipment at the source with dry hands, identify and replace the leaking device, and install a ground-fault breaker and ground wire

AnswerD. Pull the hand out immediately, cut power to the equipment at the source with dry hands, identify and replace the leaking device, and install a ground-fault breaker and ground wire

ExplanationA tingling feeling when a hand is in the water is classic stray voltage, most likely current leaking into the seawater from the cracked pump. Because of the risk of electric shock, pull the hand out immediately, do not touch equipment with wet hands, and cut power at the outlet or breaker. Stray voltage is also a chronic stress on the animals and explains the poor polyp extension and the anemone's wandering. Assuming a sting and continuing with gloves risks a shock through a gap in the glove. With no wound, the salt-sting explanation does not hold. Unplugging a cord with wet hands is the most dangerous act of all. Replace the faulty device and install a ground-fault breaker and grounding. Once the leak is fixed, the corals' condition usually improves.

IssuesThe cracked pump was kept in use without considering the risk of electrical leakage. The tank's power had no ground-fault breaker or grounding, and the corals' poor condition, a sign of stray voltage, was overlooked.

ImprovementAlways run the tank's power through a ground-fault breaker and fit ground wires to heaters and pumps. Replace any device with a crack or abnormal noise immediately and keep spares. Make a habit of cutting power before putting hands in, and suspect stray voltage when corals stay in poor condition.

In March, to remove zoanthids that had overgrown a live rock, the owner boiled the rock in a pot in the kitchen. Immediately after inhaling the steam, they developed a severe cough and runny nose, and 30 minutes later chills, fever, muscle pain, and a metallic taste in the mouth. Family members were breathing the same air in the kitchen.

What should be done first?

1. The symptoms are like a mild cold, so take over-the-counter medicine and rest
2. Turn off the heat immediately, ventilate, leave the kitchen together with the family, and call emergency services or go to the emergency room, reporting possible palytoxin poisoning
3. Keep boiling until the zoanthids are completely dead, then clean up
4. Let the rock cool and scrape the zoanthids off by hand

AnswerB. Turn off the heat immediately, ventilate, leave the kitchen together with the family, and call emergency services or go to the emergency room, reporting possible palytoxin poisoning

ExplanationZoanthids and Palythoa contain palytoxin, an extremely potent toxin; when inhaled as steam or spray from boiling, drying, or scrubbing, it causes coughing, fever, muscle pain, metallic taste, breathing difficulty, and rhabdomyolysis, and severe cases can be fatal. Once symptoms appear, turn off the heat immediately, ventilate, leave the area together with the family, and seek medical care, reporting possible palytoxin poisoning. Self-diagnosing a cold and resting is dangerous; symptoms can worsen rapidly within hours. Continuing to boil, or scraping by hand after cooling, means more exposure to the toxin. To remove zoanthids, take the rock out underwater or consult a shop; never boil, dry, or scrub them.

IssuesThe owner did not know that zoanthids and Palythoa contain palytoxin and chose boiling, the most dangerous method. The work was done in a kitchen with family present, with no ventilation or protective gear, and the risk of poisoning people was never considered.

ImprovementMake sure the whole family knows never to boil, dry, or scrub Palythoa or zoanthids. To remove them, take the rock out underwater and move it to another tank, or consult a specialist shop. Always wear gloves and eye protection and ventilate when working, and seek medical care immediately for any symptoms.

In November, fish in a 90 cm tank with corals and an anemone came down with ich. After looking it up online, the owner added the recommended dose of a copper-based fish medication to the display tank. The next morning, the toadstool leather and star polyps have deflated, the Acropora are producing mucus, and the anemone is shrunk with its mouth open. The fish's ich is unchanged.

What should be done first?

1. This shows the copper is starting to work, so continue the recommended dose
2. Double the copper concentration to cure it faster, then do a water change
3. Immediately do a large water change and remove the copper with a copper absorbent and activated carbon, and isolate the fish in a separate tank for treatment
4. Raise KH with a supplement to counteract the copper

AnswerC. Immediately do a large water change and remove the copper with a copper absorbent and activated carbon, and isolate the fish in a separate tank for treatment

ExplanationCopper is extremely toxic to invertebrates such as corals, anemones, and shrimp; even the recommended dose wipes them out within days. Once added, copper binds to live rock and sand and leaches out for a long time, so do a large water change immediately, remove it with a copper absorbent and activated carbon, and consider the rock and sand if possible. As a rule, fish are never treated in the display tank but in a separate hospital tank. Continuing or increasing copper kills the corals, and adjusting KH does not counteract copper toxicity. Remember that copper-based medications are prohibited in any tank with invertebrates. Watch the deflated soft corals and mucus-producing SPS for several days and consult a specialist shop about any that do not recover. Isolate the anemone if it melts.

IssuesThe owner did not know the basic rule that copper medications must never go into a reef tank, and acted on online information without verifying it. No hospital tank was prepared for treating fish, leaving no option but treating in the display tank.

ImprovementAlways check a fish medication's effect on invertebrates, and never use copper in the display tank. Keep a small hospital tank with heater and air pump on hand. Observe new fish in a quarantine tank for several weeks to keep disease out of the display tank.

In February, to enhance coloration, the owner dosed double the recommended amount of iodine supplement every day for 2 weeks. The toadstool leather and clove polyps are shrunk and closed, the Acropora tips are white, and some polyps are melting. There is no test kit, so the concentration is unknown. Other parameters (KH 8, nitrate 5 ppm) are normal.

What is the most appropriate response?

1. Stop dosing immediately, do 10–20% water changes for several days to lower the concentration, run activated carbon, and watch each coral for recovery
2. Color enhancement takes time, so continue for another 2 weeks
3. Add a different supplement to neutralize the iodine
4. Remove all the shrunk corals and give them an iodine-based dip

AnswerA. Stop dosing immediately, do 10–20% water changes for several days to lower the concentration, run activated carbon, and watch each coral for recovery

ExplanationIodine is needed only in trace amounts; in excess it causes soft corals to contract and SPS tissue to dissolve. Adding double the dose daily without testing very likely produced an overdose. Stop dosing immediately, continue water changes for several days to lower the concentration, run activated carbon, and watch for recovery. Continuing worsens the poisoning. There is no way to neutralize it with another supplement; that only disturbs the water further. Dipping in iodine adds more of what is already in excess. The rule is to use supplements together with a test kit and never exceed the recommended dose. Consult a specialist shop about corals that do not recover or if tissue dissolution spreads.

IssuesThe supplement was dosed above the recommended amount without testing its concentration. The owner mistakenly believed more supplement means more effect, and did not know that excess trace elements are toxic.

ImprovementAlways follow recommended doses and use only supplements that have a test kit. Introduce new supplements one at a time, starting small, and check the corals' response every 1–2 weeks. Keep a dosing log, and stop supplements first whenever something goes wrong.

In July, after the RO unit broke, the owner used plain tap water for evaporation top-off for about a week. Polyp extension on the Acropora has worsened, the clove polyps have deflated, and the star polyps will not open. Nitrate 5 ppm, specific gravity 1.024; nothing abnormal in the numbers.

What is the most appropriate response?

1. The numbers are normal, so increase the lighting to perk them up
2. Chlorine is the only problem with tap water, so add a dechlorinator and keep using it
3. Stop using tap water, do water changes with a copper absorbent and activated carbon, and use store-bought RO or purified water for top-off until the unit is repaired
4. Stop topping off for a while and let evaporation take its course

AnswerD. Stop topping off for a while and let evaporation take its course

ExplanationBesides chlorine, tap water contains copper and heavy metals from plumbing, silicate, and phosphate, all harmful to invertebrates; copper in particular impairs polyp extension even in trace amounts and kills as it accumulates. Even with nitrate and specific gravity normal, untested heavy metals can be the cause. Stop the tap water, do water changes while removing contaminants with a copper absorbent and activated carbon, and switch to RO or purified water. A dechlorinator does not remove copper or heavy metals. More light stresses weakened corals. Stopping top-off raises specific gravity and causes separate damage. Recovery can take weeks; consult a specialist shop if tissue loss appears.

IssuesNo backup was prepared for an RO unit failure, and the owner wrongly believed chlorine was tap water's only hazard. They did not consider that an untested factor (heavy metals) could be the cause, and judged it safe because the numbers were normal.

ImprovementKeep replacement RO filters and emergency store-bought RO or purified water on hand. Make it a rule never to use tap water for top-off or water changes. Top off with an auto top-off and RO reservoir, and check the reservoir level weekly.

On a June evening, the owner used insecticide spray on a fly in the room with the tank, then went to bed with the windows closed and no ventilation. The next morning, almost all the coral polyps are closed, the Acropora are producing mucus, and a shrimp is lying on its side. The tank has no lid and the skimmer draws in room air. Water parameters are unchanged from the day before.

What should be done first?

1. Closed polyps are temporary, so do nothing and wait until midday
2. Open the windows to ventilate, do a 20–30% water change and run activated carbon to remove the chemical, and draw the skimmer's air intake from a source of clean air
3. Increase the lighting to make the polyps open
4. Remove the shrimp, then spray alcohol on the water surface to break down the chemical

AnswerB. Open the windows to ventilate, do a 20–30% water change and run activated carbon to remove the chemical, and draw the skimmer's air intake from a source of clean air

ExplanationPyrethroid and similar insecticides dissolve into the water surface from the air and also enter through the skimmer's air intake. They are extremely toxic to invertebrates, and a shrimp on its side plus all corals closing at once is classic poisoning. Open the windows to ventilate the room, remove the chemical with a water change and activated carbon, and run the skimmer's air intake by tube from outdoors or a clean location. Waiting lets the toxin accumulate and progress to tissue loss. Lighting does not address the cause and stresses weakened corals. Spraying alcohol dissolves into the water and becomes a new toxin. Remember that insecticides, air fresheners, deodorizers, paint, hand cream, and the like are all enemies of the tank. Observe for several days; if tissue loss appears, frag the healthy parts and consult a specialist shop.

IssuesThe owner used insecticide spray in the room with the tank, unaware that airborne chemicals dissolve into the water. There was no ventilation, and the owner did not understand that chemicals enter through the skimmer's air intake.

ImprovementNever use sprays in the room with the tank, and make sure the family follows this too. If unavoidable, cover the tank, stop the skimmer and air pump, and ventilate thoroughly. Run the skimmer's air intake by tube from outdoors and keep activated carbon on hand. Wash cosmetics and creams off your hands before working in the tank.

At 8 p.m. on a January night, heavy snow caused a power outage, and restoration is not expected until the next morning or later. Room temperature has dropped to 15°C, and the 90 cm SPS tank is slowly cooling from 26°C. Pumps and lights are off and the surface is still. In the house there are a battery-powered air pump, blankets, disposable hand warmers, and a gas stove.

What should be done first?

1. The best thing is to do nothing and not touch the tank until morning
2. Pour hot water boiled on the gas stove directly into the tank to keep the temperature up
3. Secure flow and oxygen with the battery-powered air pump, cover the tank with blankets, and float bottles of hot water and bagged hand warmers to retain heat
4. With no lights, shine a flashlight on the surface all night to keep photosynthesis going

AnswerC. Secure flow and oxygen with the battery-powered air pump, cover the tank with blankets, and float bottles of hot water and bagged hand warmers to retain heat

ExplanationIn an outage, the first problems are oxygen shortage and stagnant water, followed by falling temperature. Secure flow and oxygen with the battery-powered air pump, cover the sides and top of the tank with blankets to prevent heat loss, and float bottles of hot water and hand warmers sealed in bags to hold the temperature. The key is never to put a heat source directly in the water. Pouring hot water in causes tissue loss from local overheating and water quality changes. Doing nothing leads to heavy losses overnight from oxygen shortage and falling pH. A flashlight is nowhere near enough for photosynthesis, and nighttime light disrupts the rhythm. After power returns, check temperature and specific gravity, and watch for bleaching and tissue loss for several days.

IssuesNo procedure had been set for keeping warmth and oxygen during an outage, so the owner did not know where to start. In a home where room temperature drops sharply in midwinter, there was no UPS or generator backup.

ImprovementKeep a battery-powered air pump with spare batteries, blankets, disposable hand warmers, and water bottles together near the tank. Get a portable power station or UPS that can run the pump and heater for several hours. Write out the outage procedure and post it next to the tank.

In August, the day before a 3-day, 2-night trip, the forecast says room temperature will exceed 35°C while the owner is away. The 60 cm reef tank has no chiller, only a cooling fan. Summer water temperature is usually around 28°C, and bleaching occurred once in the past at 29°C. There is air conditioning, but the owner planned to turn it off before leaving to save on electricity.

What is the most appropriate preparation?

1. Leave the air conditioning running at about 28°C, reduce light output and photoperiod, run the cooling fan and auto top-off, and set up temperature alerts
2. Turning the lights off completely means no heat, so it is safe to leave
3. Add several frozen water bottles before leaving to bring it down to 25°C
4. Put a sealed lid on the tank to prevent evaporation and turn off the cooling fan

AnswerA. Leave the air conditioning running at about 28°C, reduce light output and photoperiod, run the cooling fan and auto top-off, and set up temperature alerts

ExplanationHigh temperature while away is the leading cause of bleaching and total loss, and for a tank that bleached at 29°C, a 35°C room is lethal. Controlling room temperature with air conditioning is the most reliable measure; reduce light output and photoperiod to cut heat, run the cooling fan and auto top-off for evaporative cooling and stable specific gravity, and set up a temperature alert to learn of problems. Turning the lights off completely for days stops photosynthesis and weakens the corals. A temporary drop before leaving reverses within hours, and the sudden cold change is itself a stress. A sealed lid stops evaporative cooling, raising the temperature further and depleting oxygen. The animals' lives come before the electricity bill.

IssuesTemperature management while away in midsummer was taken lightly, and the owner was about to turn off the air conditioning to save money. Despite past bleaching, no chiller or alert device had been set up.

ImprovementBudget on the assumption that the air conditioning runs continuously in summer. Install an aquarium chiller and a temperature alert, and ask family or a friend to respond to problems while away. Make a pre-trip checklist and verify lighting, fan, top-off, and alert settings.

Late on a March night, an earthquake of seismic intensity 5 spilled 30% of the water from a 90 cm tank; the rockwork collapsed, corals fell onto the sand, and the anemone is shrunk beside a pump. Power is on. With the water level down, the standpipe is sucking air noisily. Part of the heater is exposed above the surface. No new saltwater has been mixed.

What should be done first?

1. Add tap water to restore the level and keep the pump running
2. Fully rebuild the rockwork first, then deal with the pump and water level
3. Temporarily stop the heater and pump, restore the level with RO water or pre-mixed saltwater, place the fallen corals in stable spots underwater, and stack the rocks low in case of aftershocks
4. Do nothing until morning and clean up when it is light

AnswerC. Temporarily stop the heater and pump, restore the level with RO water or pre-mixed saltwater, place the fallen corals in stable spots underwater, and stack the rocks low in case of aftershocks

ExplanationWith the water level down, an exposed heater can overheat and crack, and the pump may suck air and stop or fail, so stop them first. If there is no new saltwater, restore the level by adding RO or purified water a little at a time, then mix saltwater later to replace what spilled and check specific gravity. Place the fallen corals in stable spots underwater, without air exposure or contact with each other. Stack the rocks low and stable in case of aftershocks. Tap water damages corals with chlorine and heavy metals. A full rockwork rebuild takes time, during which the pump and heater stay off. Leaving it until morning spreads the damage through oxygen shortage and falling temperature. In the following days, watch the corals damaged by the fall for tissue loss.

IssuesThere was no earthquake preparation: the rockwork was not secured, the tank was not anchored against tipping, and no saltwater was pre-mixed. The owner did not know the danger of the heater and pump at low water level and had not practiced setting priorities.

ImprovementSecure the rockwork with glue or putty and stack it low. Anchor the tank stand to the wall and consider a lid to contain splashing. Always keep 10–20% of the tank volume in pre-mixed saltwater, and stock RO water. Write out the earthquake procedure (stop equipment, then water level, then animals, then rocks) and post it.

In September, with a large typhoon approaching, the municipality issued an evacuation order, and the owner expects to be unable to return home for 2–3 days. The 60 cm reef tank cannot be moved. A power outage is likely, and the owner is torn between taking the corals to the shelter and leaving them. There is one portable power station.

What is the most appropriate decision?

1. Bag up the corals and anemone and take them to the shelter
2. Leave the corals, use the portable power station to run the flow pump (or air pump) as the priority, stop the lights and feeding, clear the area around the tank, and evacuate
3. Skip the evacuation and stay home to manage the tank
4. Run only the lights on the portable power station, stop the pumps, and evacuate

AnswerB. Leave the corals, use the portable power station to run the flow pump (or air pump) as the priority, stop the lights and feeding, clear the area around the tank, and evacuate

ExplanationHuman life comes first; when an evacuation order is issued, always evacuate. Even if the corals and anemone are bagged and taken along, temperature and flow cannot be maintained at a shelter, and they melt and die in the bags. Leave the tank at home and use the limited power for the flow pump or air pump to secure oxygen and water movement, which gives the best survival rate. Corals can tolerate a few days without light, and the heater and lights would drain the power station quickly. Stop feeding to prevent water fouling. Clear the surroundings so nothing falls onto the tank. On returning, check temperature, specific gravity, and oxygen, do a water change, and then check each animal.

IssuesNo disaster priorities had been set (human life, then oxygen and flow, then warmth, then light), so the owner thought of evacuating with the pets. The capacity and use of the portable power station had not been worked out in advance.

ImprovementCalculate how many hours the portable power station can run the pump, and use a battery-powered air pump as well. Decide in advance that in a disaster people come first and the animals stay with oxygen secured. Also write out the post-evacuation procedure (check water quality, water change, observe).

In May, the owner returned from a trip to find the lighting timer had failed and the lights had stayed on at full output for 3 days. The Acropora have lost color and look whitish, the LPS are shrunk, and algae has surged on the glass. The water is slightly warm at 27.5°C. The anemone is shrunk but its foot is attached.

What is the most appropriate response?

1. Turn the lights off completely for 3 days to recover from the damage
2. To avoid a rebound from the continuous lighting, return to the normal schedule but keep the output at maximum for a while
3. Return to the normal photoperiod, reduce output by 20–30% and restore it over several days, do a water change and remove the algae, and watch for progression of bleaching
4. Dip and isolate all the bleached corals

AnswerC. Return to the normal photoperiod, reduce output by 20–30% and restore it over several days, do a water change and remove the algae, and watch for progression of bleaching

ExplanationThree days of continuous lighting causes zooxanthellae expulsion (bleaching) from light stress and lack of nighttime rest, and also drives algae growth and a temperature rise. Restoring the day-night rhythm matters most for recovery: return to the normal photoperiod, reduce output by 20–30% to protect the weakened zooxanthellae, and restore it over several days. Do a water change to restore water quality and remove the algae. Three days of total darkness stops photosynthesis and further exhausts weakened corals. Keeping maximum output continues the light stress. Bleaching is not infectious, so dipping and isolation are unnecessary; once the environment is normalized, color often returns within weeks. Frag the healthy parts of any coral that progresses to tissue loss and consult a specialist shop.

IssuesThere was no way to detect a timer failure, and the risk of lights staying on during a long absence had not been anticipated. The owner lacked knowledge that a lighting failure leads to bleaching and algae growth.

ImprovementUse both a built-in and an external timer, or a smart plug that allows remote checking. Ask family or a friend to check once a day while away. Make a return checklist (temperature, lighting, polyps, algae) and restore the environment gradually after any problem.

In April, the owner touched a carpet anemone bare-handed to reposition it and the tentacles caught the arm. After pulling free, the arm has raised welts where the tentacles touched, with intense itching and pain. Thirty minutes later the swelling is spreading and the owner is starting to feel slightly short of breath. They rubbed an eye with the hand that touched it.

What should be done first?

1. Rinse the remaining stinging cells off the arm with seawater, flush the eye under running water, and see a doctor immediately because of the shortness of breath
2. Wash the swollen area well with fresh water and alcohol, apply an over-the-counter anti-itch cream, and wait
3. Warm the arm to improve circulation and break down the venom faster
4. The swelling will subside in a few hours, so go to work as planned

AnswerA. Rinse the remaining stinging cells off the arm with seawater, flush the eye under running water, and see a doctor immediately because of the shortness of breath

ExplanationCarpet anemones have potent venom that causes welts and blisters on human skin and occasionally systemic symptoms or allergic reactions such as breathing difficulty. Rinse remaining stinging cells off the arm with seawater, not fresh water. Rubbing with fresh water or alcohol triggers more stinging cells to fire and worsens it. Rubbing an eye with the contaminated hand can damage the cornea, so flush the eye thoroughly under running water. Shortness of breath is a sign of a systemic reaction, so see a doctor immediately. Warming spreads the inflammation and swelling. Even with mild symptoms, see a dermatologist if swelling persists for days or there are blisters or fever. Always wear gloves for tank work and never touch anemones bare-handed.

IssuesThe owner did not know how potent a carpet anemone's venom is and touched it bare-handed. They did not know the basics of treating stings, such as not rubbing the eyes with the contaminated hand or rinsing with fresh water. There was also a risk of taking the shortness of breath lightly.

ImprovementWear gloves that cover to the elbow for tank work, and move anemones rock and all. Share the sting procedure with the family (rinse with seawater, no fresh water or alcohol, flush eyes under running water). Decide that breathing difficulty, dizziness, or palpitations mean emergency care.

In October, after treating a hammer coral with brown jelly disease, the owner used the same tweezers and pipette as they were to feed and reposition a torch coral and a lobo coral. The next day, one head of the torch coral shows brown jelly-like breakdown. The other LPS are still fine.

What is the most appropriate response in this situation?

1. Isolating the torch coral alone is enough; keep using the tools as they are
2. Brown jelly disease heals on its own, so improve water quality and watch
3. Soak all the LPS in dip solution overnight as a precaution
4. Isolate the torch coral immediately, cut away and dip the affected part, disinfect all tools and keep a separate set per coral, and inspect the other LPS daily

AnswerD. Isolate the torch coral immediately, cut away and dip the affected part, disinfect all tools and keep a separate set per coral, and inspect the other LPS daily

ExplanationBrown jelly disease is an infection by protozoa and bacteria that spreads to other LPS via tools and hands. Isolate the affected torch coral immediately, suction off the broken-down part, cut back to healthy tissue, and dip. Disinfect every tool used, and from now on keep separate sets for infected and healthy corals. Inspect the other LPS daily for several days and treat the same way if breakdown or foul smell appears. Isolating alone while continuing to use the tools lets the infection recur. It never heals on its own; left alone, the LPS in the tank melt one after another. Soaking all corals overnight is a major stress on healthy ones; dips should be short as a rule. If progression does not stop, consult a specialist shop the same day.

IssuesTools used to treat an infected coral were used as they were on healthy ones, causing cross-infection. The owner lacked an understanding of hygiene practices such as isolation and disinfection, and did not recognize how contagious brown jelly disease is.

ImprovementKeep separate tools and an isolation container for infected corals, and always disinfect after use. Work on healthy corals first and infected ones last. Add brown breakdown and foul smell to the daily LPS checklist, and set a procedure to isolate the same day they are found.

In June, an Acropora frag bought from a shop was put straight into the display tank without quarantine. A week later, many small white specks have appeared at the base of that frag and the neighboring Acropora, and white spots that look like bite marks are increasing on the tissue. In the dark, flat light-brown worms can be seen moving on the branches.

What is the most appropriate response?

1. The spots are algae, so scrub them off with a toothbrush
2. Remove the affected corals and treat with a dedicated dip to remove the worms, remove the eggs by hand, and always quarantine and dip new arrivals
3. Add a fish anti-parasite medication to the display tank to eradicate them
4. The worms will disappear on their own, so let the fish in the tank eat them

AnswerB. Remove the affected corals and treat with a dedicated dip to remove the worms, remove the eggs by hand, and always quarantine and dip new arrivals

ExplanationWhite specks at the base of Acropora, white bite-like spots, and flat worms moving at night are classic Acropora-eating flatworms; left alone, the whole SPS population bleaches from feeding damage and dies. Remove the affected corals, treat with a coral dip to remove the worms, and remove the eggs on the skeleton by hand or brush. As long as any worms remain they recur, so repeat the treatment every few days. Scrubbing with a toothbrush leaves both eggs and worms. Fish anti-parasite medications are toxic to invertebrates and cannot be used in the display tank. Fish do not eat enough to eradicate them. The real fix is observation in a quarantine tank and dipping at introduction to keep them out. If it spreads, consult a specialist shop.

IssuesA new frag was put directly into the display tank without quarantine, bringing in flatworms. The owner lacked knowledge of coral pests (flatworms, nudibranchs, snails) and of dip treatment at introduction.

ImprovementAlways dip new corals and observe them in a quarantine tank for 2–4 weeks before the display tank. Inspect the base and underside of the skeleton with a magnifier at introduction and remove any eggs. Check for pests regularly with a flashlight at night.

In February, an owner who has worked in a reef tank bare-handed for years developed a small reddish-purple lump on a finger joint 3 weeks ago; it has slowly grown and become ulcer-like. There is no fever and only mild pain. Over-the-counter ointment has made no difference. The hands have occasionally had small scrapes from the rocks.

What is the most appropriate response?

1. Continue the ointment and wait for a month or more
2. Washing the area with seawater will cure it, so keep doing tank work
3. See a dermatologist, mentioning the marine aquarium work, and wear gloves for all tank work until it heals
4. It is an insect bite, so switch to an over-the-counter anti-itch cream

AnswerC. See a dermatologist, mentioning the marine aquarium work, and wear gloves for all tank work until it heals

ExplanationA reddish-purple lump or ulcer on an aquarist's hand that grows over weeks is classic skin infection by a marine mycobacterium (Mycobacterium marinum), also known as fish tank granuloma. Ordinary ointments do not cure it, and the aquarium history is important for diagnosis, so always tell the doctor and see a dermatologist. Treatment may require months of oral medication. Left untreated it can spread to tendons and joints. Washing with seawater does not remove the bacteria, and continuing bare-handed work leads to reinfection. Mistaking it for an insect bite delays treatment. Wear gloves until it heals and wash hands with soap after working.

IssuesThe owner worked bare-handed for years without considering that bacteria could enter through small scrapes. They did not know that a slow-healing skin lump can be an aquarium-related infection and spent weeks on over-the-counter medication.

ImprovementAlways wear gloves for tank work and do not work with a wound on the hand. Wash hands with soap and running water afterward. Make it a family rule that a slow-healing lump or ulcer on the hand gets a doctor's visit within 2 weeks, with the doctor told about the marine aquarium.

In November, the owner is moving house and will transport a 60 cm reef tank by car over 6 hours. It holds Acropora, a hammer coral, a toadstool leather, and an anemone. The outside temperature is 10°C. The owner has heard to avoid air exposure but does not know the specific method. They have a styrofoam box, bags, and hand warmers.

What is the most appropriate transport method?

1. Submerge each animal in its own bag of tank water, squeeze out the air, pack them in the styrofoam box with hand warmers taped to the outside of the bags, and avoid direct sun and vibration
2. Put all the corals together in one large bag with less water to keep it light
3. Wrap the corals in wet newspaper and pack them in the box without water
4. Load the tank in the car with the water still in it, stop the pump, and drive

AnswerA. Submerge each animal in its own bag of tank water, squeeze out the air, pack them in the styrofoam box with hand warmers taped to the outside of the bags, and avoid direct sun and vibration

ExplanationCorals and anemones suffer tissue damage from air exposure and attack each other with stinging cells on contact, so submerge each in its own bag of tank water with the air squeezed out. A styrofoam box and hand warmers taped to the outside of the bags keep the temperature up; direct contact creates local hot spots. Avoid direct sun and vibration. Packing them together means they melt each other on contact and the anemone's mucus fouls everything. Wet newspaper without water may work for fish, but corals and anemones dry out and die. Moving the tank full of water risks the rockwork collapsing from the jolting and the tank cracking. On arrival, acclimate for at least 30 minutes and watch for tissue loss and melting for several days.

IssuesThe owner had not researched long-distance transport in advance and had no specific preparation against the three dangers: air exposure, contact, and temperature drop. The tank transport procedure had not been built into the moving plan.

ImprovementA week before transport, prepare bags, a styrofoam box, hand warmers, and new saltwater, and practice bagging each animal and maintaining temperature. Set up the tank and water at the destination first and move the animals last. For long trips, consider a specialist shop or livestock shipping service.

In August, after the water temperature briefly rose to 29°C, a torch coral has not opened at all for 5 days and its flesh is pressed flat against the skeleton. The Acropora are white but tissue remains on the skeleton. The owner cannot tell whether they are dead and should be discarded or can still be saved. The water is now 26°C and parameters are normal.

What is the most appropriate judgment and response?

1. Not opening for 5 days means dead, so discard both
2. The Acropora died when they turned white, so discard them and keep only the torch coral
3. Take both out and leave them in the air for a few minutes to check for odor
4. If tissue is attached to the skeleton, it reacts to touch, and there is no foul smell or breakdown, it is alive, so stabilize the environment and observe for several weeks

AnswerD. If tissue is attached to the skeleton, it reacts to touch, and there is no foul smell or breakdown, it is alive, so stabilize the environment and observe for several weeks

ExplanationA coral's survival cannot be judged by whether it opens. If tissue remains on the skeleton, it reacts to touch by contracting, and there is no foul smell or brown breakdown, it is alive. A bleached Acropora has only lost its zooxanthellae; with tissue remaining it can recover, so stabilize the environment and observe for several weeks. It is common for LPS to stay closed 1–2 weeks after stress. Discarding just because it will not open is premature, and taking white for dead is a mistake. Leaving it in the air for minutes dries and kills living tissue; check for odor by bringing your face close to the water. Death is indicated when the tissue is completely gone, the skeleton is exposed and growing algae, or it breaks down brown with a foul smell.

IssuesThe owner did not know the criteria for judging whether a coral is alive and tried to judge by opening and color alone. Confusing bleaching with death risked discarding corals that could recover.

ImprovementWrite out the survival criteria (tissue attached, reaction to touch, absence of foul smell and breakdown). Decide to keep the environment stable and wait at least 2–3 weeks after stress. Photograph daily and judge progression by whether the area of tissue is shrinking.

In October, in a reef tank where testing had been neglected for a while, nitrate measures 50 ppm and phosphate 0.5 ppm. The SPS are dull brown and the LPS are not opening well. Wanting to lower the numbers as fast as possible, the owner is about to drain all the tank water and replace it with new saltwater.

What is the most appropriate response?

1. Do a full water change to get back to normal at once
2. Repeat water changes of about 20% every 2–3 days, reduce feeding, and lower the levels gradually over several weeks
3. The numbers are high, so add dip medication to the display tank to reduce bacteria
4. Add 3 times the recommended dose of nitrate absorbent to lower it overnight

AnswerB. Repeat water changes of about 20% every 2–3 days, reduce feeding, and lower the levels gradually over several weeks

ExplanationNitrate at 50 ppm is high, but when corals have long been accustomed to that environment, a full water change also changes KH, pH, and trace elements all at once, and the abrupt shift causes tissue loss. The safe approach is water changes of about 20% every 2–3 days, reduced feeding to cut the supply, and a gradual decline over several weeks. A full change also upsets the bacterial balance. Dip medication in the display tank kills beneficial bacteria and harms invertebrates. Mass-dosing absorbent produces the same abrupt change, and over-correction toward zero nutrients is also dangerous. Track progress with weekly testing, and consult a specialist shop if tissue loss appears.

IssuesRegular water testing was neglected, so the deterioration went unnoticed until the numbers were far off. In a rush to fix it, the owner ignored the danger of abrupt change and nearly chose the most extreme method, a full water change.

ImprovementTest and record nitrate and phosphate weekly, and review feeding and water change volume when nitrate exceeds 10 ppm. Make a 10–20% weekly water change a habit and always correct gradually. Periodically review the balance between skimmer capacity and livestock numbers.

At 10 p.m. on a July night, the owner came home to find the water at 30°C, nearly all the SPS white with some starting to lose tissue, and the LPS and anemone shrunk. The chiller is running but cannot keep up. The shop is closed and there is no one to consult. The owner is panicking and does not know where to start.

What is the most appropriate order of priorities for the first hour?

1. Frag all the SPS first, then lower the temperature
2. Turn off the lights and do a 50% water change, then look for the cause
3. Lower the temperature gradually while increasing aeration, dim the lights, and frag and isolate healthy parts only from corals whose tissue loss is progressing
4. Do nothing and wait for the shop to open in the morning

AnswerC. Lower the temperature gradually while increasing aeration, dim the lights, and frag and isolate healthy parts only from corals whose tissue loss is progressing

ExplanationIn a tank-wide bleaching emergency, the top priorities are correcting the high temperature that caused it and securing oxygen: lower the temperature gradually at about 1°C per hour while increasing aeration, and dim the lights to reduce light stress. Then frag and isolate healthy parts only from corals whose tissue is already peeling, and let the rest recover through environmental improvement. Fragging everything takes time and makes things worse if done before cooling. A 50% water change piles on another abrupt change and does little if temperature is the cause. Left until morning, tissue loss spreads across whole colonies within hours. Consult a specialist shop the next morning and record the progression of tissue loss daily for several days. Supplement the inadequate chiller with a cooling fan and air conditioning.

IssuesThe chiller was undersized for the tank and the summer room temperature, and no emergency priorities had been set, leading to panic. The owner had no one to consult at night.

ImprovementWrite out the emergency procedure (temperature, then oxygen, then lighting, then individual corals) and post it next to the tank. Choose a chiller rated one size above the tank volume and use a cooling fan and air conditioning as well. Line up fellow keepers or a specialist shop who can be contacted at night.

At 1 a.m. on a February night, the owner, who had gone to sleep with the heating on in a tightly sealed room, looked at the tank and found all the corals closed and the fish gasping at the surface. The pH measures low at 7.6. The water is 26°C and the flow pump is running. The skimmer draws its air from the room, where 3 people are sleeping.

What should be done first?

1. Open the windows to ventilate, increase aeration, draw the skimmer's air from outdoors, and check for pH recovery and the fish's breathing
2. Add a pH booster to raise it to 8.3 at once
3. Turn on the lights to raise pH through photosynthesis
4. Move only the fish to a separate container and leave the corals as they are

AnswerA. Open the windows to ventilate, increase aeration, draw the skimmer's air from outdoors, and check for pH recovery and the fish's breathing

ExplanationWhen people sleep in a sealed room with the heating on, indoor carbon dioxide rises, dissolves into the tank water, lowers the pH, and depletes oxygen. All corals closing at once and fish gasping at the surface are the classic signs. Open the windows to ventilate, increase aeration to drive off carbon dioxide, and draw the skimmer's air from outdoors; the pH recovers within hours. Raising pH at once with a booster is an abrupt change that causes tissue loss and does not address the cause. Lights in the middle of the night disrupt the rhythm, and any effect from photosynthesis is not immediate. Moving only the fish leaves the corals short of oxygen and conditions in the container deteriorate further. If there is no improvement or fish turn on their sides, consult a specialist shop the same day.

IssuesThe owner did not know that carbon dioxide in a sealed room lowers tank pH, and the winter heating and sealed room caused an oxygen shortage. Normal pH was not on record, so the drop was not noticed until late at night.

ImprovementDraw the skimmer's air from outdoors by tube and ventilate regularly even in winter. Test pH weekly and take carbon dioxide measures if it drops sharply at night. Remember that fish gasping at the surface and all corals closing mean oxygen shortage, and be ready to aerate immediately.

On a September morning, a carpet anemone in a 60 cm tank melted overnight; its tentacles have disintegrated, the whole tank is cloudy white, and there is a strong foul smell. The clownfish are breathing hard at the surface, all the corals are closed, and the shrimp is not moving. The water is 26°C and the pump is running. The owner is unsure what to do with the remains of the anemone.

What should be done first to save the whole tank?

1. The anemone will decompose naturally, so leave it and do the water change tomorrow
2. Remove only the anemone's remains and leave the water as it is to see what happens
3. Remove all the fish and corals to a separate container and leave the display tank as it is
4. Collect all the remains, immediately do a 30–50% water change, run activated carbon and turn up the skimmer, add oxygen with aeration, and check the fish's breathing

AnswerD. Collect all the remains, immediately do a 30–50% water change, run activated carbon and turn up the skimmer, add oxygen with aeration, and check the fish's breathing

ExplanationA melting anemone releases large amounts of mucus, toxins, and ammonia, and the fish and corals in the tank die within hours. Collect all the remains with a net or by siphon, immediately do a 30–50% water change to dilute the waste and toxins, absorb them with activated carbon, turn up the skimmer to remove organics, and add oxygen with aeration. The large water change here is to stabilize the water: the danger of poisoning and oxygen shortage outweighs the danger of abrupt change. Leaving it, or waiting until tomorrow, means total loss. Removing the remains alone leaves the dissolved toxins and mucus. Moving all the animals makes oxygen and water quality hard to maintain in a container; cleaning the display tank comes first. Do another water change a few hours later, and from the next day observe for several days while testing ammonia and nitrate.

IssuesThe owner missed the signs that the carpet anemone was declining and could not isolate it before it melted. They did not recognize the danger a melting anemone poses to the whole tank or the importance of keeping saltwater ready for an emergency water change.

ImprovementCheck the anemone daily for an open mouth, shrinking, and a detaching foot, and isolate it if decline progresses. Keep 30–50% of the tank volume in pre-mixed saltwater for emergency water changes, and keep activated carbon and a battery-powered air pump on hand. Make it a rule that foul smell and cloudiness mean an immediate water change.