Catfish are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the three largest species alive, the Mekong giant catfish from Southeast Asia, the wels catfish of Eurasia, and the piraíba of South America, to detritivores, and even to a tiny parasitic species commonly called the candiru, Vandellia cirrhosa. Neither the armour-plated types nor the naked types have scales. Despite their name, not all catfish have prominent barbels or "whiskers". Members of the Siluriformes order are defined by features of the skull and swimbladder. Catfish are of considerable commercial importance; many of the larger species are farmed or fished for food. Many of the smaller species, particularly the genus Corydoras, are important in the aquarium hobby. Many catfish are nocturnal, but others are crepuscular or diurnal.
The Claroteidae are a family of catfish found in Africa. This family was separated from Bagridae. However, the monophyly of the family is sometimes contested.
The eeltail catfish are a family (Plotosidae) of catfish whose tails are elongated in an eel-like fashion. These catfishes are native to the Indian Ocean and western Pacific from Japan to Australia and Fiji. The family includes about 41 species in 10 genera. About half of the species are freshwater, occurring in Australia and New Guinea.
Trichomycteridae is a family of catfishes commonly known as pencil catfishes or parasitic catfishes. This family includes the candiru fish, feared by some people for its alleged habit of entering into the urethra of humans. They are one of the few parasitic chordates. Another species is the life monsefuano which was important to the Moche culture and still an important part of Peruvian cuisine.
The Doradidae are a family of catfishes also known as thorny catfishes, raphael catfishes or talking catfishes. These fish are native to South America, primarily the Amazon basin and the Guianas.
The Aspredinidae are a small South American family of catfishes also known as the banjo catfishes, with about 43 species.
The Ariidae or ariid catfish are a family of catfish that mainly live in marine waters with many freshwater and brackish water species. They are found worldwide in tropical to warm temperate zones. The family includes about 143 species.
The loach catfishes are a family, Amphiliidae, of catfishes. They are widespread in tropical Africa, but are most common in streams at high elevations; most species are able to cling to rocks in fast-flowing streams. The 13 genera contain 68 species.
Sisoridae is a family of catfishes. These Asian catfishes live in fast-moving waters and often have adaptations that allow them to adhere to objects in their habitats. The family includes about 235 species.
Erethistidae are a family of catfishes that originate from southern Asia. It includes about 45 species.
Bagrus is a genus of bagrid catfishes. These are relatively large catfish found in freshwater habitats in Africa, except for the virtually unknown B. tucumanus from South America, which likely is a synonym of Luciopimelodus pati.
Horabagrus is a genus of catfish in the family Horabagridae endemic to rivers in the Western Ghats in Kerala and Karnataka, India. H. brachysoma is an important food fish and members of this genus can be found in the aquarium trade.
Olyra is a genus of catfishes of the family Bagridae. This genus occurs throughout South Asia and western Indochina, from India to western Thailand.
Pseudobagrus is a genus of bagrid catfishes that inhabit streams and rivers throughout East Asia. About half of these species occur in China.
Pseudomystus is a genus of catfishes of the family Bagridae.
Bagarius is an Asian genus of catfishes of the family Sisoridae. It includes five to six extant species and potentially one extinct fossil species, B. gigas.
The bayad, is a species of bagrid catfish from Africa.
The Somalia catfish is a species of catfish in the family Bagridae. The Somalia catfish is native to the Jubba River in Somalia.
Siluranodon auritus is the only species in the genus Siluranodon of the catfish family Schilbeidae.
Horabagridae is a proposed family of catfishes containing three genera, Horabagrus, Platytropius and Pseudeutropius. Horobagrus has been more usually assigned to the family Bagridae and sometimes it has been suggested it is closer to the Schilbeidae which is where the other two genera have been more conventionally placed.
