Within the family Callichthyidae, the two subfamilies have eight genera and about 177 species. They account for about 7% of all catfish. Most of these species are in the genus Corydoras, the largest catfish genus.
The subfamily Callichthyinae contains Callichthys, Dianema, Hoplosternum, Lepth oplosternum, and Megalechis. According to a 1997 paper, Callichthys is the most basal member of the subfamily.