Oxydoras is a genus of thorny catfishes native to tropical South America.
There are currently three recognized species in this genus:
Oxydoras species are relatively large, reaching between 70 - 100 centimetres (28 - 40 in) in length. O. kneri has a maximum published weight of 9kg (20lb). O. niger gets even heavier, with a maximum published weight of 13kg (29lb).