Ancistrus hoplogenys is a species of armored catfish native to Argentina, Brazil, Guyana, Paraguay, Peru, and Uruguay, where it occurs in the basins of the Amazon River, the Essequibo River, and the Paraguay River. It has also been reported from Suriname. This species grows to a length of 15.8 centimetres (6.2 in) SL. In the aquarium hobby, this fish is sometimes known as the spotted or starlight bristlenose pleco, although it may also be referred to by its L-number, which is L059.
Ancistrus caucanus is a species of catfish in the family Loricariidae. It is native to South America, where it was at one point thought to occur in the Cauca River basin in Colombia, for which it is named, although subsequent research suggested in 2013 that it is actually native to the Magdalena River basin, whereas its congener Ancistrus vericaucanus is the species native to the Cauca. The species reaches 5.2 cm SL. It is not to be confused with the similarly named species Lasiancistrus caucanus.
Ancistrus bolivianus is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the basins of the Beni River, the Mamoré River, and the Madre de Dios River. The species reaches 8.8 cm SL.
Ancistrus jelskii is a species of catfish in the family Loricariidae. It is native to the upper Tulumayo River basin, which is part of the Ucayali River system in Peru. The species reaches 8 cm in total length.
Ancistrus triradiatus is a species of catfish in the family Loricariidae. It is native to South America, where it is known from the drainage basins of the Orinoco, the Los Guayos River, Lake Valencia, and Lake Maracaibo. The species reaches 9.2 cm SL. It sometimes appears in the aquarium trade, where it is known as the gold-spot or three-ray bristlenose pleco.
Ancistrus fulvus is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the Acará River basin in the lower Amazon River drainage in Brazil. The species reaches 8.8 cm SL.
Ancistrus multispinis is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the Atlantic coastal drainage of eastern Brazil, ranging from the Macacu River to the Maquiné River. The species reaches 14.2 cm SL. The species has nocturnal habits and has been used in studies on the impacts of deltamethrin on fish blood in Brazil.
Ancistrus tamboensis is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the Tambo River basin in the Ucayali River drainage of Peru. The species reaches 8.2 cm SL and is named for the river basin in which it occurs.
Ancistrus nudiceps is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the Takutu River basin in the upper Branco River drainage in Guyana. The species reaches 7.9 cm SL.
Ancistrus occidentalis is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the Bobonaza River basin in Ecuador. The species reaches 8.6 cm SL.
Ancistrus montanus is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in high-altitude freshwater environments, with the type specimen being collected from an elevation of around 457 m, in the Beni River basin in the upper Madeira River drainage in Bolivia. The species reaches 9.2 cm SL.
Ancistrus martini is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the Zulia River basin, which is part of the Catatumbo River drainage, which itself is part of the Lake Maracaibo drainage system in Venezuela. The species reaches 8.9 cm SL.
Ancistrus bufonius is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the Apurímac River basin in Peru. The species reaches 11.5 cm SL.
Ancistrus brevifilis is a species of catfish in the family Loricariidae. It is a freshwater fish native to South America, where it occurs in the Tuy River basin in Venezuela. The species reaches 11.8 cm SL.
Ancistrus lineolatus, also known as the Bristlenose Catfish is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the Orteguaza River basin, which is part of the Japurá River drainage in Colombia.
Ancistrus malacops is a species of catfish in the family Loricariidae. It is a freshwater fish native to South America, where it occurs in the Ampiyacu River basin in Peru. FishBase states that the species reaches 7.7 cm SL, although larger specimens, including one of 11.78 cm SL from the Gustavo Orcés V. Natural History Museum in Quito, Ecuador, are known.
Ancistrus megalostomus is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the Beni River basin, which is part of the Madeira River drainage in Bolivia. The species reaches 8.3 cm SL and is noted to inhabit high-altitude environments.
Ancistrus piriformis is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the Acaray River basin, which is part of the Paraná River drainage in Paraguay, although it has also been reported from Argentina. The species reaches 8.3 cm SL.
Ancistrus taunayi is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the Uruguay River basin. The species reaches 11.9 cm SL and at least 52.3 g in weight.
Ancistrus trinitatis is a dubious species of catfish in the family Loricariidae. It is known only from the Caribbean, where it occurs in freshwater environments on the island of Trinidad in Trinidad and Tobago. This species is of uncertain validity, as Theodore Gill referred to the type material in 1858 as Ancistrus guacharote and it was later described by Albert Günther in 1864 as Chaetostomus trinitatis, but neither description is considered sufficient to determine the validity and identity of the taxon. While the original locality of the type material was listed as Puerto Rico, this was determined to be in error and the material was determined to have actually originated from the Maracaibo Basin of Venezuela. In 1946, Henry Weed Fowler described the species Ancistrus maracasae from Trinidad, and in 2019, Lesley S. De Souza, Donald C. Taphorn, and Jonathan W. Armbruster determined that A. maracasae and A. trinitatis are synonymous, designating the holotype of A. maracasae as the neotype of A. trinitatis, although sources such as FishBase and ITIS list the two species as valid but separate.
