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.
Loricariidae is the largest family of catfish, with over 90 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.
The zebra oto or tiger oto is a fish of the genus Otocinclus of the family Loricariidae that originates from Peru.
Hypancistrus is a genus of loricariid catfish originating from the Amazon basin in South America. Unlike many of the other Loricariids, however, some Hypancistrus species are more carnivorous and enjoy meat in their diet. Hypancistrus species are popular aquarium fish, including such popular fish as the zebra pleco and Queen Arabesque pleco.
Peckoltia is a genus of small South American armored suckermouth catfishes. Many of these fish are popular aquarium fish.
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.
Corymbophanes is a genus of armored catfish native to South America where they are only known from Guyana. Corymbophanes was originally placed in its own tribe Corymbophanini, but the first comprehensive molecular phylogenetic analysis of the subfamily Hypostominae found Corymbophanes to be nested within the tribe Ancistrini.
Neoplecostomus is a genus of fish in the family Loricariidae native to South America. Neoplecostomus can be distinguished from all other loricariids by a modified shield of small plates on the abdomen with posteriorly directed odontodes; the shield appears to act as a holdfast. The color pattern is generally mottled brown with the abdomen white. The head is long, rounded, and shovel-shaped. The fin spines are weak. They range from about 8 to 11 cm (3.1–4.3 in) SL. The species of Neoplecostomus live in fast-flowing water.
Pareiorhina is a genus of armored catfishes native to South America where they are only found in Brazil. These species are known to occur at altitudes above 650 metres (2100 ft) in various rivers of the Grande, Paraíba do Sul, São Francisco and Tietê River basins. This genus was first erected by Gosline in 1947 as a monotypic genus to include Rhinelepis rudolphi. It was not until 2003 that a second species, P. carrancas, was described. The third species, P. brachyrhyncha was described in 2005. Pareiorhina forms a monophyletic subunit with Neoplecostomus within the subfamily Neoplecostominae.
Neoplecostomus corumba is a species of armored catfish endemic to Brazil. This species grows to a length of 7.83 centimetres (3.08 in) SL.
Neoplecostomus espiritosantensis is a species of armored catfish endemic to Brazil where it is found on the eastern slope of the Serra do Mar in the Jacu and São Lourenço Rivers. This species grows to a length of 10.3 centimetres (4.1 in) SL.
Neoplecostomus franciscoensis is a species of armored catfish endemic to Brazil where it is found in the headwaters of the Das Velhas and Paraopeba River basins. This species grows to a length of 7.5 centimetres (3.0 in) SL.
Neoplecostomus granosus is a species of South American armored catfish where it is possibly found in Brazil. This species grows to a length of 8.6 centimetres (3.4 in) SL.
Neoplecostomus paranensis is a species of armored catfish endemic to Brazil where it is found in the upper Paraná River basin. This species grows to a length of 9.3 centimetres (3.7 in) SL.
Neoplecostomus selenae is a species of armored catfish endemic to Brazil. This species grows to a length of 10.17 centimetres (4.00 in) SL.
Neoplecostomus variipictus is a species of armored catfish endemic to Brazil where it is found in the Paraíba do Sul River basin. This species grows to a length of 9.0 centimetres (3.5 in) SL.
Neoplecostomus yapo is a species of armored catfish endemic to Brazil. This species grows to a length of 10.96 centimetres (4.31 in) SL.
Neoplecostomus ribeirensis is a species of armored catfish endemic to Brazil where it occurs in the Ribeira de Iguape River basin. This species grows to a length of 9.0 centimetres (3.5 in) SL.
Neoplecostomus watersi is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the upper Paraná River basin in the state of Goiás in Brazil. It is typically found at the bottom of clear rivers with rocky substrates. The species reaches 7 cm (2.8 in) in standard length. Its specific name, watersi, honors Roger Waters of Pink Floyd.
Neoplecostomus altimontanus, or high mountain armored catfish, was discovered in 2010 and also 2023 while surveying rivers in Minas Gerais, Brazil. It is described as having a sort of armor of bony plates, and copper-colored teeth. It grows to 4 inches in length. The species have broad heads and moderately sized eyes. It also has a blotchy pattern and ranges from a creamy color to a dark grayish-brown to a yellow brown. Males and females can be told apart because males have shorter and more robust teeth while females have slender teeth, and more teeth.
