Ancistrus is a genus of nocturnal freshwater fish in the family Loricariidae of order Siluriformes, native to freshwater habitats in South America and Panama. Fish of this genus are common in the aquarium trade where they are known as bushynose or bristlenose catfish. In the aquarium hobby they are often referred to as bushynose or bristlenose plecos instead, but this may lead to confusion as "pleco" usually is used for Hypostomus plecostomus and its allies and is often used as a catchall term for any loricariids remotely resembling that species.
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 cryptophthalmus is a species of catfish in the family Loricariidae. It is a troglomorphic species that is native to South America and occurs only in the São Vicente and Angélica-Bezerra cave system in the Paranã River basin, which is part of the Tocantins River drainage in Brazil. The species reaches 6 cm (2.4 in) SL. Alongside Ancistrus galani and A. formoso, this species displays characteristics unusual among loricariids, such as reduced pigmentation and atrophied eyes, which are adaptations to a subterranean habitat that can be found in various types of cavefish.
Ancistrus macrophthalmus is a species of catfish in the family Loricariidae. It is native to South America, specifically found in the Orinoco River and its lower tributaries in Venezuela. The species reaches 7.9 cm (3.1 in) SL. It is occasionally seen in the aquarium trade, where it is one of multiple species sometimes referred to as "medusa plecos".
Ancistrus galani is a species of catfish in the family Loricariidae. It is native to South America, where it occurs only in Los Laureles Cave, at an elevation of 650 m (2,130 ft) above sea level, in the Socuy River basin, which is part of the Lake Maracaibo drainage system in the state of Zulia in Venezuela. The species reaches 5.6 cm (2.2 in) SL and was named after Carlos Galan, a Venezuelan speleologist. A. galani differs from most Ancistrus species in having an unpigmented body, atrophied or entirely absent eyes, and highly reduced ocular orbits, which are all thought to be adaptations to its dark subterranean habitat and stygobitic lifestyle.
Ancistrus parecis is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the Tapajós River basin in Brazil. Its specific epithet refers to the Parecis Plateau, where the type specimen was collected. The species reaches 6 cm (2.4 in) SL.
Ancistrus amaris is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the Orinoco River and Apure River basins in Venezuela. The species reaches at least 11.57 cm (4.56 in) SL and was described in 2019 by Lesley S. de Souza of the Field Museum of Natural History, Donald C. Taphorn of the Royal Ontario Museum, and Jonathan Armbruster of Auburn University alongside five other species of Ancistrus.
Ancistrus saudades is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the basins of the Takutu River, the Ventuari River, the Caroní River, and the Caura River in Guyana, Venezuela, and Brazil. The species reaches at least 10.75 cm (4.23 in) SL and was described in 2019 by Lesley S. de Souza of the Field Museum of Natural History, Donald C. Taphorn of the Royal Ontario Museum, and Jonathan Armbruster of Auburn University alongside five other species of Ancistrus.
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 (3.6 in) SL. It sometimes appears in the aquarium trade, where it is known as the gold-spot or three-ray bristlenose pleco.
Ancistrus ranunculus is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the basins of the Xingu River, Trombetas River and the Tocantins River in Brazil. It inhabits areas with clear water and without strong currents, and it is known to inhabit narrow cracks in submerged rocks, small passages, and spaces below flat rocks. The species is large for a member of Ancistrus, reaching 19.5 cm (7.7 in) in total length. It sometimes appears in the aquarium trade, where it is one of several species known as a medusa pleco, although it may be referred to by its L-number, L034.
Ancistrus lithurgicus is a species of catfish in the family Loricariidae. It is a freshwater species native to South America, where it occurs in the basins of the Essequibo River and Berbice Rivers in Guyana. The species reaches 13.2 cm (5.2 in) 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 (5.6 in) SL. The species has nocturnal habits and has been used in studies on the impacts of deltamethrin on fish blood in Brazil.
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, and the Cuyuni River in Venezuela. The species reaches 7.9 cm (3.1 in) SL.
Ancistrus yutajae is a species of catfish in the family Loricariidae. It is native to South America, where it occurs only in the Yutajé River in Venezuela. The species reaches at least 8.28 cm (3.3 in) SL and was described in 2019 by Lesley S. de Souza of the Field Museum of Natural History, Donald C. Taphorn of the Royal Ontario Museum, and Jonathan Armbruster of Auburn University alongside five other species of Ancistrus.
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 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 falconensis is a species of catfish in the family Loricariidae. It is a freshwater species native to South America, where it occurs in the Hueque River and the Ricoa River in the state of Falcón in Venezuela. The species reaches at least 16.12 cm SL and was described in 2010 by Donald C. Taphorn, Jonathan W. Armbruster, and Douglas Rodríguez-Olarte on the basis of morphological differences from the species Ancistrus gymnorhynchus, which occurs in a similar geographic region.
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 (4.7 in) SL and at least 52.3 g (1.84 oz) in weight.
Ancistrus patronus is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the Orinoco basin in Venezuela and Colombia. The species reaches at least 8.7 cm (3.4 in) SL and was described in 2019 by Lesley S. de Souza of the Field Museum of Natural History, Donald C. Taphorn of the Royal Ontario Museum, and Jonathan Armbruster of Auburn University alongside five other species of Ancistrus. Its specific name means "defender" in Latin and was given to the species due to the reported tendency of male A. patronus to actively guard their nests and protect their young until they are relatively large.
