Osteogaster

The bronze cory, Osteogaster aenea, long known as Corydoras aeneus, is an armoured catfish described from Trinidad and accepted to occur across much of South America. That range looks more like a complex of similar, distinct species than a single one, and fish from outside Trinidad are of uncertain identity. Aquarium fish are almost all commercially farmed, and the names C. schultzei and C. venezuelanus are routinely misapplied to them.

Osteogaster eques, long known as Corydoras eques, is an armoured catfish described from the Amazon at Codajás, on the rio Solimões main channel in western Brazil. Its wider range is unclear, although similar-looking fish have been exported from Peru on occasion. It is sometimes confused with C. venezuelanus, and two similar unidentified fishes from Peru carry the codes CW007 and CW043.

The green-gold cory, Osteogaster melanotaenia, long known as Corydoras melanotaenia, is an armoured catfish from the Rio Meta basin in Colombia. It lives in small tributaries, creeks, flooded forest and sand banks. Also known as the 'elongate bronze cory', it resembles C. aeneus at first glance, but is more elongate and has a golden-yellow tinge to the fins.

The rusty cory, Osteogaster rabauti, long known as Corydoras rabauti, is an armoured catfish known mostly from the rio Javarí, which forms much of the border between Brazil and Peru. It possibly also occurs in Colombia, but the full extent of its range is somewhat unclear. Often confused with the very similar C. zygatus, it can be told apart by the broad dark stripe on the upper body, which extends onto the lower part of the caudal peduncle. An albino form is available on occasion.

The black band cory, Osteogaster zygata, long known as Corydoras zygatus, is an armoured catfish from the middle Río Marañón watershed in eastern Ecuador and northern Peru. Also known in the trade as the 'zygus cory', it looks very similar to Corydoras rabauti. In C. zygatus the broad dark stripe on the upper body stops short of the lower caudal peduncle, and in C. rabauti it extends onto it.