Discus

Discus plague-like syndrome

SignsWhole body turns black, slime coat peels off in white sheets, fins clamped, motionless in a corner, rapid decline

PreventionQuarantine new fish in a separate tank for 2–3 weeks. Avoid water-quality drops right after mixing new fish

Hole-in-the-head disease

SignsWhite pits or dents on the head or lateral line, white stringy feces, weight loss and refusal to eat

PreventionIncrease water changes and keep water clean. Vary the diet to avoid nutritional imbalance

Gill flukes (Dactylogyrus)

SignsOne gill cover held open, rapid gill movement, rubbing gill covers on objects, gasping at the surface

PreventionBe careful with new fish and live food; quarantine. Watch gill movement daily

Refusal to eat / darkening

SignsIgnores food, darkens and hides in a corner, clamped fins, thins out along the back

PreventionKeep 28–30°C and slightly acidic pH stable. Check for bullying and provide hiding places

Intestinal parasites / white stringy feces

SignsWhite, translucent, stringy feces; swollen belly; weight loss despite eating

PreventionAlways thaw and rinse frozen bloodworms. Check feces color and shape daily

Ich (white spot) / gill disease

SignsWhite spots on the body, rapid gill-cover movement, excess slime and a whitish body

PreventionKeep temperature swings within 2°C per day. Match temperature when changing water

Torn fins / fin rot

PreventionNo sharp driftwood or decor. Scoop with a container instead of chasing with a net

First aidDo a 1/3 water change and keep water clean. If fin edges turn white and dissolve, isolate and use fish medication as directed

Skin abrasions

PreventionPrevent fighting among discus; provide hiding places and enough space

First aidIf the wound turns white and cottony, it is fungus. Isolate and change water; if it worsens, get advice the same day

Jumping out / falls

PreventionAlways use a tank lid. Avoid sudden lights that startle the fish

First aidReturn gently with wet hands and boost aeration. See a vet if the skin has dried badly

Heater burns

PreventionFit a heater guard. Do not place the heater near hiding spots

First aidWatch for whitening or peeling at the site. Keep water clean; if it spreads, isolate and get advice

Nontuberculous mycobacterial infection

RouteThrough cuts on hands that touched tank water or fish

PreventionKeep cut hands out of the tank. Wash hands with soap after working

Aeromonas infection

RouteTank water or mucus from sick fish contacting a wound

PreventionWear gloves. See a doctor for red swelling or fever

Salmonellosis

RouteOral infection from hands that touched tank water or equipment

PreventionDo not wash equipment in the kitchen sink. Wash hands thoroughly

Pseudomonas and other waterborne bacteria

RouteTank water entering eyes, wounds, or mouth

PreventionNever start a siphon by mouth. Rinse eyes with running water if splashed

Food

• Discus-specific pellets as the staple, 2–3 times a day
• Frozen bloodworms and discus beefheart mix as supplements
• Only what is eaten in 2–3 minutes. Always remove leftovers

Water

• 28–30°C, pH 6.0–6.8, slightly acidic soft water
• 2–3 times a week, change 1/3–1/2 with dechlorinated water at the same temperature

Toys & play

• No toys needed. A stable environment is the best stimulation
• Driftwood and cones serve as hiding places and spawning sites
• Companions to school with (5 or more) give psychological stability

Nest, bed & hideout

• Unglazed spawning cones or vertical flat surfaces
• Driftwood or plant cover where weak fish can retreat

Bedding & litter

• A bare-bottom tank (no substrate) is recommended for easy cleaning
• If using gravel, keep it thin so leftovers do not accumulate
• Remove feces and leftovers from the bottom daily with a pipette

Cage / housing material

Glass or acrylic tank. Lid required. Heater with guard

Size & space

At least 90 cm (180 L) for 5 fish. At least 30 L per adult

Layout

• Place heater and thermometer at opposite ends
• External or hang-on filter plus separate aeration
• 1–2 pieces of driftwood or cones as hiding places

Placement notes

• Avoid direct sunlight and high-traffic areas
• Use a stand that can bear the weight of a filled tank

Exercise, free-roam & walks

• No walks needed. Open swimming space is all the exercise required
• 8–10 hours of light a day to set a day-night rhythm
• Do not startle. No sudden lights or tapping on the glass

Temperature & humidity

Temperature28–30°C (up to 31–32°C during treatment)

HumidityHumidity not an issue. Watch for condensation and mold in the room

Summer & winter

• Summer: use cooling fans or a chiller to stay below 32°C
• Winter: keep a spare heater in case of failure. Insulation

Nail trimming

No nail trimming. Instead, remove leftovers and feces daily and change water 2–3 times a week

Brushing, skin & coat care

Do not touch the skin. The slime coat is key to immunity. Scoop with a container, not a net

Other care

Rinse filter media lightly in tank water. Check thermometer and heater operation daily

Protection from predators

• Secure the lid so cats cannot reach into the tank
• Only peaceful tank mates. Avoid fin-nipping species
• Prevent outside hitchhikers such as mosquito larvae

Foreign-body ingestion

Use substrate and decor too large to fit in the mouth. If gravel is swallowed, wait for it to be spat out; if it stays lodged, get advice

Being stepped on

Watch your feet during water changes and moves so you do not step on a fallen fish. If one falls, return it to the water quickly with wet hands

Getting pinched

Beware of fish getting wedged in gaps around the lid or filter. Fit a sponge on the intake so fins are not sucked in

Falls

A lid is essential because startled fish jump. If one falls to the floor, return it at once, boost aeration, and watch for whitening of dried areas

Escape

Escape means jumping out. Seal gaps and avoid sudden lights at night. Never release into the wild

Safe release procedure

1. Quietly separate fighting or chasing fish with a container or divider
2. Isolate the weaker fish in a separate tank or behind a divider
3. Keep temperature stable and add aeration to calm them
4. Check fins and skin for wounds and keep the water clean

After the release

If wounds turn white and cottony or red and raw, consult a fish-disease store or vet

What to tell the vet & what to bring

Temperature, pH, ammonia and nitrite readings, water-change frequency, date acquired, photos and video of symptoms, and a sample of tank water

Checking consciousness, breathing & heartbeat

• Watch the gill covers. Normal is about 60–80 beats per minute
• Floating or sinking on its side is a sign of critical condition
• Confirm 28–30°C and zero ammonia and nitrite

Stopping bleeding

• Do not touch the fish; keep the water clean and wait for bleeding to stop
• Check the bleeding fin or skin and isolate from other fish
• If bleeding continues or spreads, get advice the same day

Transport

• Fill a bag with tank water and oxygen and place it in a dark box
• Keep above 28°C with insulation, avoid shaking, and arrive within 30 minutes