Discus: Round, colourful cichlids from the Amazon basin.

Discus are freshwater cichlids native to the Amazon river basin in Brazil. They are prized for their round shape and bright colours, making them a staple of the global aquarium trade. Aquaculture in Asia supports a major industry supplying hobbyists worldwide.

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Native to the Amazon river basin in Brazil
Parents feed fry with skin secretion for four weeks
Captive breeds can grow up to 23 cm in length
Major aquaculture industry based in Southeast Asia
Highly social fish that form large groups

What it is

Discus belong to the genus Symphysodon, a group of cichlids known for their distinctive laterally compressed bodies. Unlike their relatives the angelfish, they lack extended fins, giving them a rounded disc shape. Their sides display patterns in green, red, brown, and blue. Wild specimens reach about 15 cm, though captive breeds can grow larger. Males and females look similar until maturity, when males develop pointed dorsal fins and thicker lips.

Where it lives

These fish inhabit the lowland Amazon basin in Brazil. Different species occupy specific water types. The Heckel discus prefers blackwater habitats in the Rio Negro and nearby rivers. Other species live in clearwater or whitewater areas east and west of the Purus Arch. They favour lentic environments like floodplain lakes and flooded forests where suspended material is low.

How it lives

Discus are highly social and often form large groups, which is unusual for American cichlids. They feed on algae, detritus, and small invertebrates, possessing long intestines typical of herbivores. Invertebrates make up a smaller part of their diet compared to predatory cichlids. They move away from the main group when breeding to protect their young from cannibalism.

Breeding and life cycle

Parental care is highly developed in this genus. Both parents tend to the eggs and fry. Uniquely, adults produce a skin secretion known as discus milk. The larvae feed on this mucus for their first four weeks. This transfer of microorganisms helps ensure high survival rates for the young. Sexual maturity is reached within one year.

A drawing made by EveryFish from what this page says. It is a diagram, not a picture of the real fish.

Fish and people

Aquarists value discus for their calm behaviour and striking colours. They are considered challenging to keep due to strict water quality needs and social requirements. A large tank is necessary for their size. Captive breeding has produced variants like turquoise and pigeon blood. Southeast Asia hosts a major aquaculture industry that supplies the global market. Competitions celebrate these bred strains.

S. Aequifasciata Axelrodi. Photo: Gladstone Peixoto Moraes, Public domain, via Wikimedia Commons

The best of discus breeder fish in Spain and Portugal. www.biotopica.net. Photo: Biotopica, criadero de peces disco, CC BY-SA 4.0, via Wikimedia Commons

Questions people ask about Discus

What do discus fish eat in the wild?

They primarily consume algae, plant material, and detritus. Small invertebrates also form part of their diet, especially during the high-water season. Their long intestines suggest an omnivorous or herbivorous feeding strategy.

How do discus parents care for their young?

Both parents guard the fry. For the first four weeks, the young feed on a nutrient-rich skin secretion produced by the adults. This unique behaviour helps transfer beneficial microorganisms to the offspring.

Are discus fish difficult to keep in an aquarium?

Yes, they are considered challenging. They require stable water parameters, particularly pH levels, and must be kept in groups. Large tanks of at least 210 litres are recommended due to their size and social nature.

Good reading and sources

Where this page comes from

The facts on this page come from the Wikipedia article "Discus (fish)", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.

It may contain mistakes, and figures change over time. Nothing here is investment or buying advice. If something is wrong, tell us. Last refreshed 2026-11-15.

Photo credits on this page

The small pictures above come from Wikimedia Commons under free licences. Some are cropped to fit.