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.
Otocinclus is a genus of catfish in the family Loricariidae native to South America, commonly known as "dwarf suckers" or "otos". This genus, like other loricariids, is characterized by rows of armour plating covering the body, as well as the underslung suckermouth. They are generally small in size; O. tapirape is the smallest of the species (2.4 cm), while O. flexilis is the biggest (5.5 cm). These species have adaptations that allow them to breathe air. A duct forms at the junction between the esophagus and the stomach and expands into an enlarged, ring-like diverticulum, characteristic of this genus, which allows air-breathing. Otocinclus are popular aquarium fish, and they are often purchased as algae eaters. It is difficult to breed them in captivity, and only wild caught Otocinclus are available to hobbyists. This genus is widely distributed east of the Andes of South America, throughout the lowlands from northern Venezuela to northern Argentina, but are generally absent from the Amazon and the Orinoco lowlands.
Hyphessobrycon is a genus of freshwater fish in the family Characidae. These species are among the fishes known as tetras. The genus is distributed in the Neotropical realm from southern Mexico to Río de la Plata in Argentina. Many of these species are native to South America; about six species are from Central America and a single species, H. compressus is from southern Mexico.
Astyanax is a genus of freshwater fish in the family Characidae of the order Characiformes. Some of these fish, like many of their relatives, are kept as aquarium pets and known collectively as tetras. With around 150 described species and new ones being described yearly, this genus is among the largest of the entire order; Hyphessobrycon also has more than 145 species and which one is larger at any one time depends on whether more species have been recently described in one or the other. The blind and colorless cave tetra of Mexico is a famous member of the genus, but its taxonomic position is disputed: Some recognize it as part of the Mexican tetra and this is supported by phylogenetic evidence, but others recognize the cave form as a separate species, A. jordani.
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.
Astroblepus is a genus of fish in the family Astroblepidae found in South America and Panama. This genus is the only member of its family. These catfishes are primarily found in torrential streams in the Andean area. Astroblepus pholeter and A. riberae are troglobites adapted to living in subterranean water systems. These species are typically small, less than 10 cm (4 in). The largest species reaches 30 cm (1 ft). These fish have suckermouths like those of loricariids. They have two pairs of barbels, maxillary and nasal. The dorsal fin spine lacks a locking mechanism. These fish also have odontodes, tiny teeth on their skin. All species exhibit a conical, pointy type on their fin rays like that found in other loricarioids; other species also exhibit a blunt type that is only found on their skin.
Farlowella is a genus of fish in the family Loricariidae native to South America. This genus is broadly distributed in Amazon, Orinoco, Paraná and coastal rivers of the Guyana Shield. It is absent from the Pacific slope of the Andes and from the coastal rivers of the Brazilian Shield. Many of these species are kept in aquariums. This genus has a unique body shape that resembles a thin stick of wood. The body is slender and elongate, often with a pronounced rostrum and a brownish color with two lateral dark stripes beginning at the tip of the rostrum, passing over the eyes and ending at the tail, which are periodically interrupted on the caudal peduncle.
Pimelodus is a genus of fish in the family Pimelodidae native to Central and South America.
Loricariichthys is a genus of catfishes of the family Loricariidae.
Sturisoma is a genus of armored catfishes native to Central and South America.
Parotocinclus is a genus of fish in the family Loricariidae native to South America. This genus is distributed through almost all hydrographic systems in South America from the Guyana Shield drainages and Amazon Shield tributaries to the coastal drainages of eastern and southeastern Brazil, including the rio São Francisco basin. Most species have the caudal peduncle oval in cross section. It has been found that Characidium species may interact with P. maculicauda. The small Characidium will follow grazing P. maculicauda, which release particulate matter dislodged from the catfish's foraging.
Ochmacanthus is a genus of pencil catfishes native to South America. These species are distributed in South America. O. alternus and O. orinoco originate from the Rio Negro and Orinoco River basins of Brazil and Venezuela. O. batrachstoma inhabits the Paraguay River basin in Brazil. O. flabelliferus lives in river drainages in Guyana and Venezuela. O. reinhardtii is known from the Amazon River basin in Brazil and drainages in French Guiana.
Ituglanis is a genus of small freshwater fish in the family Trichomycteridae native to South America. Their greatest diversity seems to occur in the Amazon River basin. Most species inhabit leaf litter, with several species living in caves.
Rhamdia is a genus of three-barbeled catfishes found in Mexico, Central and South America. These catfishes are nocturnal, opportunistic carnivores, found in a wide range of freshwater habitats. This genus includes a number of troglobitic members, encompassing a number of taxa, including R. enfurnada, R. guasarensis, R. laluchensis, R. laticauda, R. macuspanensis, R. quelen, R. reddelli and R. zongolicensis. In a few of these only some of their populations are troglobitic.
Cetopsorhamdia is a genus of three-barbeled catfishes native to South America.
Chaetostoma, also known as the bristlemouth catfish, is a genus of suckermouth armored catfishes native to South America with one species, C. fischeri, extending into Panama. Most species inhabit flowing rivers in the lower Andes and its foothills. Some species are kept in unheated aquaria.
Creagrutus is a genus of characins found mostly in South America, with one species C. affinis extending into Panama in Central America.
Steindachnerina is a genus of toothless characins from South America, with 24 currently described species:
Imparfinis is a genus of three-barbeled catfishes native to South America, with a single species in Central America.
Pimelodella yaharo is a species of three-barbeled catfish belonging to the family Heptapteridae. It is native to the freshwater systems of South America, specifically the Sierra Nevada de Santa Marta in Colombia.
