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.
Airbreathing catfish are fish comprising the family Clariidae of the order Siluriformes. About 14 genera and about 116 species of clariids are described. All the clariids are freshwater species. Note that other groups of catfish also breathe air, such as the Callichthyidae and Loricariidae.
Loricariidae is the largest family of catfish, with 92 genera and just over 680 species. Loricariids originate from freshwater habitats of Costa Rica, Panama, and tropical and subtropical South America. These fish are noted for the bony plates covering their bodies and their suckermouths. Several genera are sold as "plecos", notably the suckermouth catfish, Hypostomus plecostomus, and are popular as aquarium fish.
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. Another species is the life monsefuano which was important to the Moche culture and still an important part of Peruvian cuisine.
The Pimelodidae, commonly known as the long-whiskered catfishes, are a family of catfishes.
The Cetopsidae are a small family of catfishes, commonly called the whale catfishes.
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 Bagridae are a family of catfish that are native to Africa (Bagrus) and Asia from Japan to Borneo. It includes about 245 species. These fish are commonly known as naked catfishes or bagrid catfishes.
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.
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".
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.
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.
The Delturinae are a subfamily of catfishes of the family Loricariidae, including two genera, Delturus and Hemipsilichthys. This group is sister to all other loricariids except Lithogenes. The geographical distribution of Delturinae, exclusively on the southeastern Brazilian Shield, indicates southeastern Brazil acts as either a refugium for basal loricariid taxa or a point of origin for the Loricariidae.
Liobagrus is a genus of catfishes of the family Amblycipitidae. Liobagrus fishes are distributed in the Yangtze River basin, Taiwan, Japan, and the Korea Peninsula. The adipose fin of these fishes is a confluent with the caudal fin. The nostrils are far apart, unlike those found in Amblyceps. Most Liobagrus species grow to about 100 millimetres (3.94 in) SL.
Notoglanidium depierrei is a species of catfish family Claroteidae. This species is endemic to Cameroon where it is known only from its type locality of the Sanaga River Basin. It reaches a length of about 17.2 centimetres (6.8 in) SL. It was formerly considered to be the sole member of the monotypic genus Platyglanis but this has now been synonymised with Notoglanidium.
Parauchenoglanis is a genus of claroteid catfishes native to Africa.
Auchenoglanis is a genus of relatively large, up to 70 cm (2.3 ft) SL, claroteid catfishes native to various freshwater habitats in Africa.
Notoglanidium is a genus of claroteid catfishes native to Africa. The formerly recognized genera Anaspidoglanis, Liauchenoglanis and Platyglanis have all been merged into Notoglanidium.
