rm
Passport
- Family
- Discus
- Grows to
- 14 cm (5.5")
- Lives
- 10–15 years
- Temperament
- Peaceful
- Care
- Advanced
- Swims
- Mid-water
- Keep
- In a group of 5 or more
- Water
- 26–30 °C (79–86 °F)
ColombiaPeruBrazil
Care requirements
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On record for Discus: adult size, lifespan, minimum tank, temperature, ph, hardness, minimum group, diet, care level, swim level, tank length.
A figure that is not on record is left out rather than guessed. One marked Suggested comes from keeping knowledge rather than a page.
- Minimum tank 255 L / 67.4 US gal
- pH 5–8
- Hardness 0–12 dGH
- Diet omnivore
- Tank length 120 cm minimum
Care notes written from general aquarium knowledge, not from the cited sources.
About
Discus are the fish people work up to. A disc-shaped body the size of a saucer, patterned in reds, blues, greens and browns, moving slowly and deliberately through open water — a group of adults in a big planted tank is about as impressive as freshwater fishkeeping gets.
They're demanding rather than delicate. Warmth, cleanliness, company and food are all needed in larger measure than for anything else in this catalogue, and falling short on any of them shows quickly.
They also do something almost no other fish does: the parents secrete a nutritious mucus from their skin and the fry feed on it directly, grazing off their parents' flanks for the first weeks of life.
Tank setup
Keep your discus warm. They want the top of the tropical range and they want it steady — this is the single requirement that rules out most community tanks, because the fish you would otherwise keep with them cannot take that heat.
Give them height as well as length. They're tall fish and a shallow tank looks and feels wrong for them.
Keep a proper group, and treat the minimum on the grid above as a floor rather than a target. Discus are social and hierarchical: a lone fish, or a pair with nothing else for company, tends to be nervous and off its food, and the more of them there are the further the pecking order spreads.
Keep the tank calm and the light moderate. They're easily startled and a busy tank keeps them stressed.
Soft, slightly acidic water suits them, especially for breeding, though modern farmed stock is adaptable.
Feeding
Discus need feeding often and well, and this is where the workload is.
Feed several times a day, particularly with growing fish. Quality discus pellets, frozen bloodworm, brine shrimp and beefheart-based preparations are the usual staples.
Feed a varied diet. Discus fed one thing exclusively become fussy and refuse anything else, which becomes a problem the day that food is unavailable.
Avoid: underfeeding growing fish, which produces permanently stunted adults, and avoid leaving uneaten food in a warm tank.
Filtration and flow
Filter heavily and change water generously and often. Frequent feeding means a heavy waste load, and warm water accelerates everything.
Keep the flow gentle. They're slow, deliberate swimmers and a strong current is unwelcome.
Warm water holds less oxygen, so surface movement and good circulation matter more than in a cooler tank.
With plants
Discus are safe with plants and won't eat them.
The constraint is the temperature. Many popular aquarium plants struggle at discus warmth, so choose species that tolerate it — amazon swords, anubias, java fern and cryptocorynes are the reliable options.
Tall plants and wood suit their shape and give them something to feel enclosed by.
Health
They show stress faster and more visibly than almost any fish. Dark colouration, clamped fins and hiding are the early signs, and the cause is usually water quality, temperature, or bullying.
Their skin and gills are sensitive. Internal parasites and hole-in-the-head are the conditions most associated with them, and both trace back to poor water and poor diet more often than to infection alone.
Quarantine new arrivals properly. Discus are expensive and an introduced disease moves through a group quickly.
Breeding
They pair off from a group, spawn on a vertical surface — a cone, a plant leaf, the glass — and both parents guard the eggs.
The remarkable part comes after hatching. The fry attach to the parents' flanks and feed on the mucus they secrete, and the pair take turns carrying them. Removing the parents too early kills the brood outright.
Soft acidic water is needed for the eggs to develop. Beyond that, the difficulty is having a genuine pair — they choose each other, and buying two fish and hoping rarely works.
Tank mates
Avoid35
- Common Pleco Common Pleco grows to 45 cm against Discus at 14 cm, big enough to eat it.
- Least Killifish Discus grows to 14 cm against Least Killifish at 2 cm, big enough to eat it.
- Scarlet Badis Discus grows to 14 cm against Scarlet Badis at 2 cm, big enough to eat it.
- Amano Shrimp Discus is not safe with Amano Shrimp: discus and shrimp and yabbies are a bad pairing.
- Bala Shark Bala Shark is not safe with Discus: discus and sharks are a bad pairing.
Only with care34
- Chinese Algae Eater Chinese Algae Eater is aggressive and Discus is peaceful.
- Convict Cichlid Convict Cichlid is aggressive and Discus is peaceful.
- Jewel Cichlid Jewel Cichlid is aggressive and Discus is peaceful.
- Agassiz's Dwarf Cichlid Discus is a risk to Agassiz's Dwarf Cichlid: discus and sth american cichlids - dwarf are a pairing to watch.
- Angelfish Discus and Angelfish are an uneasy mix: angelfish and discus are a pairing to watch.
No conflict is recorded with the other 37 species in the database, so nothing to flag. 2 species are not covered at all, so they could not be judged either way.