Discus are a genus of three species of cichlid freshwater fishes native to the Amazon River basin. Discus are popular as aquarium fish and their aquaculture in several countries in Asia is a major industry
Discus belong to the genus Symphysodon, which currently includes two (or three) species:
- Symphysodon Discus (suggested names for subspecies - see below)
- Tefe Discus
There is disagreement on the taxonomy. Commonly three species have been accepted, but recent studies suggest two species since Symphyson aequifasciata and Symphyson discus share the same genes, while the Symphysodon tarzoo has different mtDNA.
Location and habitatEdit
The three species of Symphysodon have different geographic distributions. S. aequifasciatus occurs in the Rio Solimões, Rio Amazonas and the Río Putumayo-Içá in Brazil, Colombia and Peru. In contrast the distribution of S. discus appears to be limited to the lower reaches of the Abacaxis, Rio Negro and Trombetas rivers. S. tarzoo occurs upstream of Manaus in the western Amazon.
Like cichlids from the genus Pterophyllum, all Symphysodon species have a laterally compressed body shape. In contrast to Pterophyllum, however, extended finnage is absent giving Symphysodon a more rounded shape. It is this body shape from which their common name, "discus", is derived. The sides of the fish are frequently patterned in shades of green, red, brown, and blue. The height and length of the grown fish are both about 20–25 cm (8–10 in).
Reproduction and sexual dimorphismEdit
Another characteristic of Symphysodon species is their care for the larvae. As for most cichlids, brood care is highly developed with both the parents caring for the young. Additionally, adult discus produce a secretion through their skin, which the larvae live off during their first few days. This behaviour has also been observed for Uaru species. However when bred in captivity the larvae will tend to live off their parents secretion for up to 2 weeks.