History
Symphysodon aequifasciatus and Symphysodon discus. The latter species, Symphysodon. discus, was described by the German ichthyologist Heckel in 1840 and has therefore been saddled with the common name Heckel discus ever since. This is also the name under which it is sold in the hobby.
The specific name discus refers to its discoid shape, whereas the generic name Symphysodon has as its Greek roots,"odonto" = tooth and "symphyso" = growing together, referring to the jaws of the fish and the positioning of their teeth only on the symphysis (point of fusion) of the jaw (bones) resulting in reduced dentition relative to other cichlids (Borror 1971,Kullander 1986).
Symphysodon discus is found in the lower Negro, Trombetas and Abacaxis rivers of Brazil (Kullander 1986).
The Heckel discus is immediately recognizable and distinguishable from the other species (Symphysodon . aequifasciatus), which was first described by Pellegrin in 1904 as a subspecies (S. discus var. aequifasciatus), but was later elevated to full species status.S.aequifasciatus is found chiefly along the Brazilian Amazon, and west into Peru (Rios Solimoes and Putumayo), and east to Belem into the Rio Xingu system (Kullander 1986).
Domestic discus were then bred from these. There are occasional wild discus available but they are rare in the aquarium trade and quality is normally not too good.