Osteogaster is one of the genus names that emerged from a 2024 phylogenetic revision splitting the old, catch-all genus Corydoras (family Callichthyidae) into several narrower lineages. Its species are the classic armored catfish of South American lowland streams and floodplains, small (1.5–3 in in the atlas) and heavily plated, with a downturned, barbelled mouth for sifting the substrate and the ability to gulp air at the surface and absorb oxygen through the gut - a well-known corydoradine adaptation for low-oxygen water. Atlas coverage spans a wide range of the continent, from Brazil, Colombia, Peru, and Venezuela down to Argentina, Bolivia, Paraguay, and Trinidad and Tobago.
This genus includes one of the aquarium hobby's most important fish: the bronze corydoras (Osteogaster aenea), a beginner staple prized for its hardiness, peaceful schooling temperament, and easy breeding, long available in both wild-type and albino forms. Several other atlas entries in this hub - among them the horseman cory, fire cory, and green-gold cory - are still catalogued under the older "Corydoras" name pending the same reclassification working through hobby usage and the broader literature, so the group here spans both names in transition. The conservation picture is mild overall, with most assessed species Least Concern and a single Vulnerable listing.