Cetopsidae

The Cetopsidae, the whale catfishes are a small family of freshwater ray-finned fishes belonging to the order Siluriformes. The fishes in this family are found in South America.

==Taxonomy== This family contains five genera divided into two subfamilies, Cetopsinae and Helogeneinae. Helogeneinae was previously a family-level group, but now it has been reclassified as a subfamily of Cetopsidae. This subfamily contains four species in the genus Helogenes. The subfamily Cetopsinae contains four genera. Cetopsidium contains six species, Cetopsis contains 21 species, Denticetopsis contains seven species, and Paracetopsis contains three species; this makes a total of 37 cetopsines. The genera have been changed as recently as 2005 with the genera Bathycetopsis, Hemicetopsis, and Pseudocetopsis set in synonymy with Cetopsis and the description of the new genus Cetopsidium.