Discus
Symphysodon aequifasciatus
advanced careOverview
The discus (Symphysodon aequifasciatus) is often called the king of the aquarium — a large, round, luminous cichlid from the slow Amazon backwaters. It is also genuinely demanding: warm, soft, spotless water, a big tank and a group of companions of its own kind. Discus reward experienced keepers with a decade or more of striking, personable fish, but they are the wrong choice for a first tank.
Tank & water
A group needs a large, tall tank — at least 250 litres (60 gallons) to start, and more for six-plus adults. Our large-tank guide covers suitable options.
- Very warm: hold 28–30 °C with a reliable, correctly sized heater.
- Soft and acidic: pH 6.0–7.0 and low hardness suit them best; monitor closely with a test kit.
- Pristine: heavy biological filtration plus frequent, generous water changes to keep nitrate low — see a safe nitrate level.
Feeding
Discus are carnivore-leaning omnivores. Feed a varied diet of quality discus pellets or flakes, frozen bloodworm, brine shrimp and specialist beef-heart or discus mixes. They eat slowly and deliberately, so feed several small meals and remove uneaten food promptly to protect water quality.
Tankmates
Choose only calm, heat-tolerant fish that thrive at 28–30 °C: cardinal tetras, rummynose tetras, sterbai corydoras and peaceful characins. Avoid boisterous, nippy or cool-water species. Many keepers run a species-only tank to keep conditions perfect. Keep stocking light and quarantine all newcomers — see our quarantine guide.
Discus — frequently asked questions
Are discus hard to keep?
Yes — discus are an advanced fish and not a first project. They need a large, very warm tank, soft slightly acidic water and pristine conditions with frequent water changes. They are sensitive to poor water quality and stress. With disciplined maintenance they are hardy and long-lived, but they punish neglect.
How many discus should I keep together?
At least five, ideally six or more. Discus are social shoaling cichlids that feel exposed in small numbers, where a dominant fish may bully the rest. A group spreads aggression and settles them, which is why the tank has to be large from the start.
What temperature do discus need?
Warmer than almost any community fish — 28–30 °C. This rules out many common tankmates that cannot tolerate such heat. The high temperature also raises their oxygen and water-quality demands, so strong biological filtration and regular water changes are essential.
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