Symphysodon tarzoo
Symphysodon tarzoo, the green discus, is a species of cichlid native to rivers of the western Amazon Basin upriver from the Purus arch, although it occasionally occurs downstream. An introduced population in the Nanay River is based on stock from the Tefé region. The green discus is found in blackwater habitats with a high temperature of and low pH of 4.8–5.9. Although also known from whitewater, its preference for lentic habitats such as floodplains means that the water contain little suspended material.
This species grows to a length of SL. S. tarzoo has red spots on the anal fin and body, which separates it from other discus species.
The scientific name was coined by Earl Lyons in 1959, and the species was revalidated by pattern, morphology and mtDNA in 2006. Later studies have confirmed its distinction, although some suggest the correct scientific name for the green discus is S. aequifasciatus. No natural hybrids are known between the green discus and its relatives.
