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.
Callichthyidae is a family of catfishes, called armored catfishes due to the two rows of bony plates along the lengths of their bodies. It contains some of the most popular freshwater aquarium fish, such as many species in the genus Corydoras.
Airbreathing catfish comprise the family Clariidae of the order Siluriformes. Sixteen genera and about 117 species of clariid fishes are described; all are freshwater species. Other groups of catfish also breathe air, such as the Callichthyidae and Loricariidae.
The Ictaluridae, sometimes called ictalurids, are a family of catfish native to North America, where they are an important food source and sometimes fished for sport. The family includes about 51 species, some commonly known as bullheads, madtoms, channel catfish, and blue catfish.
The walking catfish is a species of freshwater airbreathing catfish native to Southeast Asia. It is named for its ability to "walk" and wiggle across dry land, to find food or suitable environments. While it does not truly walk as most bipeds or quadrupeds do, it can use its pectoral fins to keep it upright as it makes a wiggling motion with snakelike movements to traverse land. This fish normally lives in slow-moving and often stagnant waters in ponds, swamps, streams, and rivers, as well as in flooded rice paddies, or temporary pools that may dry up. When this happens, its "walking" skill allows the fish to move to other aquatic environments. Considerable taxonomic confusion surrounds this species and it has frequently been confused with other close relatives. One main distinction between the walking catfish and the native North American ictalurid catfish with which it sometimes is confused, is that the walking catfish lacks an adipose fin. It can survive 18 hours out of water.
The channel catfish is North America's most numerous catfish species. It is the official fish of Kansas, Missouri, Nebraska, and Tennessee, and is informally referred to as a "channel cat". In the United States, they are the most fished catfish species with around 8 million anglers targeting them per year. They also have very few teeth and swallow food whole. The popularity of channel catfish for food has contributed to the rapid expansion of aquaculture of this species in the United States. It has also been widely introduced in Europe, Asia and South America, and it is legally considered an invasive species in many countries.
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.
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.
Cranoglanis is the only genus of armorhead catfishes.
Loricarioidea is a superfamily of catfishes. It contains the six families Trichomycteridae, Nematogenyiidae, Callichthyidae, Scoloplacidae, Astroblepidae, and Loricariidae. Some schemes also include Amphiliidae. This superfamily, including Amphiliidae, includes about 156 genera and 1,187 species.
Hemiancistrus is a genus of suckermouth armored catfishes. These species are native to South America. The taxonomy of this genus is complex and unclear, and major work has to be done. Many of these fish are popular aquarium fish.
Conorhynchos conirostris is a species of catfish.
Pinirampus pirinampu is a species of catfish of the family Pimelodidae. P. pirinampu is also known as the flatwhiskered catfish.
Harttia is a genus of armored catfishes native to South America.
Cavefish or cave fish is a generic term for fresh and brackish water fish adapted to life in caves and other underground habitats. Related terms are subterranean fish, troglomorphic fish, troglobitic fish, stygobitic fish, phreatic fish, and hypogean fish.
Fonchiiichthys uracanthus is a species of armored catfish native to Costa Rica and Panama. However, Fonchiiichthys has recently been considered to be a synonym of Rineloricaria and thus may be invalid. This species grows to a length of 16.5 centimetres (6.5 in) SL.
'Pseudancistrus' megacephalus is a species of catfish in the family Loricariidae. It is of uncertain and disputed classification.
Guyanancistrus niger is a species of catfish in the family Loricariidae that is of disputed classification. It is native to South America, where it occurs in the Oyapock basin in French Guiana. Though reportedly uncommon, it is typically seen in rapids where the species Pseudancistrus barbatus is also present, although the ecological relationship between the two is not known. The species reaches 15.9 cm in standard length, although it has been reported to reach 25.4 cm, and it may be a facultative air-breather.
Cryptancistrus similis is a species of catfish in the family Loricariidae and the only member of the monotypic genus Cryptancistrus. It is a freshwater fish native to South America, where it occurs in the upper Paru de Oeste River in Brazil. The species reaches 6.2 cm in standard length. It was described in 2018 by Sonia Fisch-Muller, Jan Mol, and Raphael Covain as part of a taxonomic review of the genus Guyanancistrus, which Cryptancistrus was found to be distinct from but closely related to. Its specific epithet, similis, is derived from Latin and references the species' similarity to the species of Guyanancistrus, specifically Guyanancistrus brevispinis.
