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.
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.
Hisonotus is a genus of armored catfishes native to South America. Species of Hisonotus and Curculionichthys are the only representatives of the subfamily Otothyrinae having serrae on the posterior edge of the pectoral fin spine. These species are small fishes, generally found in small fast flowing streams, where they grasp to the branches and leaves of aquatic or subaquatic plants. The species of this genus mostly occur in Atlantic coastal streams of southern Brazil and the Paraguay-Paraná system of southern South America. They are also distributed in the Río de La Plata basin and coastal rivers of southeastern Brazil.
Loricariichthys is a genus of catfishes of the family Loricariidae.
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.
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.
Brycon is a genus of fish in the family Characidae found in freshwater habitats in Central and South America, ranging from southern Mexico to northern Argentina. Despite not being closely related to true trout, they are sometimes called South American trout. Members of the genus may be referred to by a number of other different common names in various languages. They reach a maximum length of 11.9–79.5 cm (4.7–31.3 in) depending on the species involved. Some species perform seasonal breeding migrations.
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.
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.
Bryconamericus is a genus of characins found in Central and South America.
Creagrutus is a genus of characins found mostly in South America, with one species C. affinis extending into Panama in Central America.
Characidium is a genus of fish in the family Crenuchidae. They are mainly found in South America, but C. marshi is from Panama. They are small, slender fish that live on the bottom in flowing fresh waters and feed on small animals such as insects.
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.
Dolichancistrus is a genus of suckermouth armored catfishes native to South America.
