Oxydoras is a genus of large thorny catfish (family Doradidae) from the river systems of tropical South America, with atlas species - Kner's thorny catfish (O. kneri), the black doradid (O. niger), and Sifontes's talking catfish (O. sifontesi) - recorded from Bolivia, Brazil, Colombia, Venezuela, Argentina, Paraguay, Peru, and Uruguay, spanning much of the Amazon, Orinoco, and Parana-Paraguay drainages. Like other doradids they carry a row of bony, hook-like scutes along the flank in place of true scales, a heavily armored head, and stout serrated pectoral and dorsal spines; the family's "talking catfish" nickname comes from the audible sounds some species make by grinding the pectoral spine against its socket or drumming the swim bladder.
This is a genus of genuinely large catfish - atlas species run 27.5–31.5 in - so while thorny doradids as a family are a long-standing presence in the South American catfish hobby, Oxydoras species are a proposition for very large aquaria or outdoor ponds rather than typical home tanks; juveniles are occasionally traded but quickly outgrow standard setups. They are omnivorous, nocturnal bottom-feeders that use their long maxillary barbels to forage over sand and mud. Conservation data are thin - most of the genus is Not Evaluated by the IUCN - which is typical for large, wide-ranging Neotropical catfish that are more often assessed as fisheries resources than through dedicated red-list review.