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.
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.
Leporinus is a genus of fish in the family Anostomidae native to South America. The fossil species Leporinus scalabrinii, known from the late Miocene of Entre Ríos in Argentina, has only recently been added to this genus after being misidentified as a species of primate under the name Arrhinolemur scalabrinii for over 100 years.
Roeboides is a genus of characins from Central and South America. These fish, among other characteristics, are small, are typically translucent, and have a rhomboid shape.
Pimelodus is a genus of fish in the family Pimelodidae native to Central and South America.
Brycon insignis, the Tiete tetra, is a species of fish in the family Characidae. It is endemic to the Paraíba do Sul River basin in southeast Brazil. B. insignis migrates upstream to spawn and has traditionally been important to fisheries, but it is now a threatened species.
Pimelodella is a genus of three-barbeled catfishes.
Bryconops is a genus of freshwater fish in the family Iguanodectidae from South America. It consists of small fish, all under half-a-foot long, with slender bodies and silvery scales, though there is some mild color variation. Several species can be identified by way of a humeral patch, and others have a reddish ocellus, or eyespot, on one or both lobes of the dorsal fin.
Moenkhausia is a genus of freshwater fish in the family Characidae native to tropical and subtropical South America. These are medium-sized tetras where the largest species only reach around 12 cm (4.7 in).
Salminus, popularly known as dorado or dourado, is a genus of relatively large, predatory freshwater fish from the family Characidae. They are native to large tropical and subtropical rivers in South America, and undertake migrations during the rainy season to spawn. They are very popular among recreational anglers and also support important commercial fisheries.
Creagrutus is a genus of characins found mostly in South America, with one species C. affinis extending into Panama in Central America.
Hemibrycon is a genus of characins. They are mainly found in South America, Trinidad in the Caribbean), and H. dariensis of east Panama.
Hemigrammus is a genus of freshwater fish in the family Characidae native to South America and commonly seen in the aquarium trade. These are medium-small tetras where the largest species reach up to around 11 cm (4.3 in).
Knodus is a genus of characins, small freshwater fish from South America.
Metynnis is a genus of serrasalmid fish from tropical and subtropical South America. They are herbivorous or omnivorous, and inhabit a wide range of freshwater habitats, ranging from rivers and streams, to floodplains, flooded forests, lakes, pools and reservoirs. They generally reach 8–15 cm (3–6 in) in standard length, although a few species may reach up to 18 cm (7 in). The genus contains many of the species known as silver dollars in the aquarium trade.
Myloplus is a genus of freshwater fish in the family Serrasalmidae found in tropical and subtropical South America, where they inhabit rivers and streams. They are primarily herbivores, but also take some animal matter. Depending on the exact species, they reach up to 16–56 cm (0.5–1.8 ft) in standard length. Adult males have a double-lobed anal fin and filamentous extensions on the dorsal fin, and both sexes can be brightly colored when breeding.
Cyphocharax is a genus of fish in the family Curimatidae native to South America.
Iguanodectidae is a family of freshwater fish in the order Characiformes that lives in South America. It is home to the subfamily Iguanodectinae and the monotypic Bryconops clade. Several species in the family, such as the green line lizard tetra, the tailspot tetra, and the orangefin tetra, are sometimes taken as aquarium fish.
Bryconops alburnoides is a small freshwater fish, approximately 6 inches long at its largest, that lives in the rivers of South America. It has a slender body, with a yellowish dorsal fin and yellow-tinged back scales that fade into silver on its belly. It is largely an insectivore that picks land-dwelling insects from the riverbanks, though it eats much more whenever rain washes prey into the water.
