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.
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 stream catfishes comprise the family Akysidae of catfishes.
The shark catfishes form the family Pangasiidae. They are found in fresh and brackish waters across southern Asia, from Pakistan to Borneo. Among the 30-odd members of this family is the plant-eating, endangered Mekong giant catfish Pangasianodon gigas, one of the largest known freshwater fish. Several species are the basis of productive aquaculture industries in Vietnam's Mekong Delta.
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.
The Chiapas catfish, Lacantunia enigmatica, is an unusual species of catfish from the Usumacinta River basin in the Mexican state of Chiapas and in Guatemala. It was scientifically described in 2005 and placed in its own family Lacantuniidae. While discovery of an undescribed species of catfish is not uncommon, discovery of a new family of any vertebrate group is a rare event. The Chiapas catfish mainly feeds on crabs, prawns, small fish, and large, tough plant seeds. This catfish is commonly fished in its natural habitat, where it is known as madre de juil, which means "mother of Rhamdia".
Rineloricaria is a genus of freshwater tropical catfish belonging to the family Loricariidae. They are commonly called whiptail catfish because of the long filament that grows out of the tip of the caudal fin that is characteristic of the genus. With the exception of R. altipinnis from Panama, they are native to the rivers of northern and central South America. Some species are regularly seen in the aquarium trade.
Chaca is the only genus in the catfish family Chacidae. These fish are commonly known as squarehead catfishes, frogmouth catfishes, or angler catfishes. These unusual fish have a sedentary lifestyle and spend much of their time motionless.
Loricariinae is a subfamily of the family Loricariidae of catfish. This subfamily is divided into two tribes and about 30 genera. They are mainly native to freshwater habitats in South America, but there are also several species in Panama and a single (Fonchiiichthys) in Costa Rica.
Pseudecheneis is a genus of sisorid catfishes native to Asia.
The Somalia catfish is a species of catfish in the family Bagridae. The Somalia catfish is native to the Jubba River in Somalia.
Galeichthys is a genus of sea catfishes in the family Ariidae, the only genus in the subfamily Galeichthyinae. It includes four predominantly marine species distributed in Southern Africa and northwestern South America:
Arius is a genus of catfishes of the family Ariidae. The genus Arius is distributed in brackish and fresh waters of Eastern Africa and south to Southeast Asia.
Batrachocephalus mino, the beardless sea catfish, is the only species of catfish in the genus Batrachocephalus of the family Ariidae. This species occurs in marine and brackish waters of Bay of Bengal, and parts of the western central Pacific, in coastal waters, estuaries, and lower reaches of rivers. It is distributed from Pakistan, India, Sri Lanka, Bangladesh, Myanmar, Malaysia, Thailand, to Indonesia.
Ketengus typus, the bigmouth sea-catfish, is the only species in the sea catfish genus Ketengus.
Neoarius graeffei, or blue salmon catfish, is a species of catfish found in freshwater rivers of Australia and Papua New Guinea. This species is most identifiable by its large, shark-like dorsal fin that is led by a poisonous spine. Like other catfish, the blue salmon catfish is known to use electrical pulses to sense prey in the water. This prey sensing mechanism may be the reason that these catfish are known to eat the land dwelling hopping mouse at a high rate.
