Symphysodon tarzoo, the green discus, is a species of cichlidendemic to Brazil; specifically, to rivers of the western Amazon Basin upriver from the Purus arch, although it occasionally occurs downstream.[2][3] An introduced population in the Nanay River is based on stock from the Tefé region.[4] The green discus is found in blackwater habitats with a high temperature of 27–30 °C (81–86 °F) and low pH of 4.8–5.9.[4] Although also known from whitewater, its preference for lentic habitats such as floodplains means that the water contain little suspended material (unlike main sections of whitewater rivers).[3][5]
This species grows to a length of 13.2 centimetres (5.2 in) SL.[2][6]S. tarzoo has red spots on the anal fin and body, which separates it from other discus species.[7]
The scientific name was coined by Earl Lyons in 1959, and the species was revalidated by pattern, morphology and mtDNA in 2006.[2][7] Later studies have confirmed its distinction, although some suggest the correct scientific name for the green discus is S. aequifasciatus (a name typically used for the blue/brown discus).[3][4] No natural (wild) hybrids are known between the green discus and its relatives.[2][4]
^ abcdReady, J.S.; Ferreira, E.J.G.; Kullander, S.O. (2006). "Discus fishes: mitochondrial DNA evidence for a phylogeographic barrier in the Amazonian genus Symphysodon (Teleostei: Cichlidae)". Fish Biology. 69: 200–211. Bibcode:2006JFBio..69S.200R. doi:10.1111/j.1095-8649.2006.01232.x.
^ abcdBleher, H.; Stölting, K.N.; Salzburger, W.; Meyer, A. (2007). "Revision of the genus Symphysodon Heckel, 1840 (Teleostei: Perciformes: Cichlidae) based on molecular and morphological characters". Aqua. 12: 133–174.
