Symphysodon aequifasciatus

Symphysodon aequifasciatus, the blue discus or brown discus, is a species of cichlid native to rivers of the eastern and central Amazon Basin downriver from the Purus Arch. This discus is found in black-, clear- and whitewater, but its preference for lentic habitats such as floodplains and flooded forests means that the whitewater it inhabits contain little suspended material (unlike main sections of whitewater rivers). It is largely restricted to water with a high temperature of 25–32 °C (77–90 °F) and a pH of 5.2–7.7.

It typically reaches a length of up to 15.2 centimetres (6 in) SL, but captives have been claimed to reach 23 cm (9 in). It is commonly kept in aquariums.