Discus Symphysodon aequifasciatus/discus/tarzoo/haraldi

Discus are unusually-shaped for cichlids, being laterally thin, large discs, mostly brightly-coloured. They are native to the Amazon Basin.

There are currently considered to be 3 species in the genus, but taxonomy remains complex and in discussion. Assigning individuals to these species is further complicated by many hybrids and colour/pattern mutations bred in aquaculture.

In 2006, the genus was distilled into 3 species: aequifasciatus (blue or brown discus), discus (red or henkel) and tarzoo (green). In 2007, these were changed again: tarzoo became aequifasciatus and aequifasciatus became haraldi. This has been challenged and some authorities recognise 4 species or more. Each species has a geographical niche (eg the Henkel is native to the Rio Negro area).

Most wild Discus are shy and have vertical stripes to camouflage them among reeds, grasses and other plants.

Discus can reach 15cm (6 inches) long in the wild and larger in captivity.

They are gregarious, shoaling fish although a pair will move from the group to breed, to avoid cannibalisation of fry by the group.

Green Discus. Parents care for their young and secrete a mucus on their bodies for the fry to eat. Adults eat mainly algae and small invertebrates.