Pufferfish (ornamental)

Overgrown teeth

SignsMouth will not close; pecks at food but cannot eat; mouth looks white and protruding; weight loss

PreventionFeed shell-on snails or clams at least twice a week to wear the teeth down. Never keep on dry food alone

Ich (white spot disease)

SignsSalt-grain white spots on body and fins, rubbing against objects, rapid gill movement

PreventionQuarantine new fish for 2 weeks. Avoid sudden temperature changes; match temperature and salinity at water changes

Internal parasites (wasting)

SignsEats but the belly sinks in; thin white stringy feces; back becomes thin and bony

PreventionDwarf puffers are often wild-caught, so quarantine and observe after purchase. Check feces color and thickness daily

Salinity mismatch

SignsBody darkens; black blotches on the belly; loss of appetite; sits motionless on the bottom (brackish species kept in fresh water)

PreventionFor green spotted and figure-eight puffers, measure with a hydrometer and raise salinity gradually over weeks as they grow

Obesity / indigestion

SignsOnly the belly stays constantly swollen; no feces; vomits food; sluggish

PreventionAvoid fatty foods and overfeeding. Fast one day a week; feed only what is eaten in a few minutes

Bacterial skin infection

SignsRed sores on the body; white film; fins rotting away; red swelling around the mouth

PreventionScaleless skin is vulnerable to poor water quality. Keep ammonia and nitrite at zero; change water weekly

Bite wounds from conspecifics or other fish

PreventionHouse alone as a rule. If keeping dwarf puffers in groups, plant densely and provide many hideouts

First aidIsolate the bitten fish at once and rest it in clean water. Chunks missing from eyes or fins heal naturally. See a vet if a white film appears

Inflation and abrasions from netting

PreventionNetting startles the fish into inflating and damages the skin. Move it in a cup or container with the water

First aidKeep it submerged and transfer into a container underwater so it does not swallow air. Monitor wounds in clean water; see a vet if redness spreads

Heater burns

PreventionFit a heater guard. Do not leave gaps in the tank where the fish can wedge itself against the heater

First aidWhitened skin is prone to infection. Change water to keep quality high; if the sore spreads, go to a fish-treating vet

Jumping out

PreventionJumps when startled. Seal gaps in the lid and around cord holes; keep the water level at least 5 cm below the lid

First aidEven if dried out, return it gently to the water with bare wet hands and increase aeration. Keep it dark and quiet and observe for several hours

Tetrodotoxin poisoning

RouteNot from the aquarium water, but from eating the fish

PreventionOrnamental puffers are also toxic. Never eat one, even after it dies. Dispose of it so children and cats cannot get at it

Nontuberculous mycobacterial infection

RouteThrough cuts on hands that touch tank water or fish

PreventionWear gloves if you have cuts on your hands. Wash with soap after tank work. See a dermatologist if a red lump persists

Vibrio infection

RouteCuts on the hands exposed to brackish or salt water

PreventionTake special care with brackish tanks. Do not put cut hands in the water. Immunocompromised people should wear gloves

Salmonellosis

RouteHand-to-mouth after touching tank water, filter media, or substrate

PreventionAlways wash hands after water changes or cleaning filter media. Do not wash tank equipment in the kitchen sink

Food

• Frozen bloodworms and frozen brine shrimp 1–2 times a day, only what is eaten within a few minutes
• Shell-on snails, clams, and shell-on shrimp at least twice a week to wear the teeth down
• Will accept prepared food once trained, but use it as a supplement, not a staple

Water

• Freshwater species: dechlorinated water. Brackish species: match the specific gravity with marine salt mix
• Ammonia and nitrite at zero, nitrate low. Change one-third of the water weekly

Toys & play

• Add snails regularly; cracking and eating them cares for the teeth and relieves boredom
• A maze-like layout of plants and driftwood to swim through
• It learns its owner, so talk to it at the tank and feed it from your hand

Nest, bed & hideout

• Provide several dense plant thickets or ceramic tubes to hide in while resting
• For brackish species, add coral rock or driftwood as hideouts

Bedding & litter

• Freshwater species: aquarium soil or fine sand. Choose a substrate with no sharp edges
• Brackish species: coral sand to keep pH stable on the high side
• Leftover food rots quickly, so remove uneaten food from the substrate daily

Cage / housing material

Glass tank with a lid. Filter, heater, thermometer, hydrometer (brackish species)

Size & space

At least 10 L per dwarf puffer. Adult green spotted puffer: 60 cm tank or larger, kept alone

Layout

• Create several hideouts so a bitten fish has somewhere to escape
• Fit a sponge over the filter intake and keep the flow gentle
• Use a guarded heater and leave no gaps where the fish can get wedged

Placement notes

• Keep out of direct sunlight and away from vibration, on a stable dedicated stand
• Brackish water corrodes equipment, so protect nearby metal and power outlets from salt creep

Exercise, free-roam & walks

• No walks needed. Time spent hunting for food and swimming space are its exercise
• Coming over when the owner approaches is a sign of good health
• If it spends more time sitting on the bottom, test the water quality and temperature first

Temperature & humidity

TemperatureWater temperature 24–28°C. Keep it constant with a heater; avoid sudden changes

HumidityNo humidity control needed. Top up evaporation with fresh water so salinity does not concentrate

Summer & winter

• In summer, above 30°C means oxygen depletion. Use a cooling fan and extra aeration
• A heater is essential in winter. Keep insulation and a battery-powered air pump ready for power outages

Nail trimming

Tooth care instead of nail trimming. If the mouth is hard to close, increase shell-on shellfish; have overgrowth trimmed at a vet

Brushing, skin & coat care

No coat care needed. Scaleless, delicate skin, so do not touch with hands or nets; test the water weekly

Other care

For brackish species, measure salinity with a hydrometer and convert gradually to brackish or seawater over several weeks as the fish grows

Protection from predators

• Use a heavy lid so cats cannot reach into the tank
• Avoid community tanks; it nips the fins of other fish
• Do not place outdoors or by a window; protect from birds and strong sunlight

Foreign-body ingestion

It can swallow fine gravel or shell fragments along with food and get a blockage. Feed pieces sized to the mouth and use a fine substrate with no sharp edges

Being stepped on

No risk of being stepped on, but a fish that has jumped out is hard to spot on the floor. Check the floor after tank work and return it to the water even if dried out

Getting pinched

Can get wedged at the filter intake or between the heater and the glass. Fit a sponge on the intake and a guard on the heater

Falls

A tank tipping or falling is the biggest accident risk. Use a dedicated stand with an anti-seismic mat. Carry the fish in a container with its water; never lift it in a net

Escape

Jumps out when startled. Use a gap-free lid and lower the water level. If found, return it gently to the water with bare hands and observe for several hours

Safe release procedure

1. Keep your hand still underwater and wait for the fish to let go
2. If it does not let go, gently bring another piece of food to its mouth underwater
3. Separate fighting fish with a divider and move the bitten one to another container
4. Wash human bite wounds under running water and disinfect, bearing in mind bacteria in the water

After the release

If a human wound becomes red and swollen, see a dermatologist. Let fish bite wounds heal naturally in clean water; see a vet if a white film or rot appears

What to tell the vet & what to bring

Species, body length, years kept; water temperature, specific gravity, and water test readings; diet; tank mates; photo of feces. Bring a sample of the tank water

Checking consciousness, breathing & heartbeat

• Are the gills moving? (normal is roughly 60–120 per minute)
• Do the eyes or body react to a finger brought close? Is the body darkened?
• Even if on its side or inflated, recovery is possible as long as the gills are moving

Stopping bleeding

• Bleeding from fins or skin stops on its own in clean water
• Add a slime-coat protectant at the labeled dose; keep specific gravity steady for brackish species
• If bleeding continues or spreads, go to a fish-treating vet

Transport

• Put it in a container with its tank water, without a net, so it does not inflate
• Keep warm in a styrofoam box, dark, and carry without jolting