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.
The Serrasalmidae (serrasalmids) are a family of characiform fishes, recently elevated to family status. It includes more than 90 species. The name means "serrated salmon family", which refers to the serrated keel running along the belly of these fish. Fish classified as Serrasalmidae are also known by these common names: pacu, piranha, and silver dollar. These common names generally designate differing dental characteristics and feeding habits.
Ossubtus is a genus of fish in the family Serrasalmidae. It contains a single species, Ossubtus xinguense, the parrot pacu or eaglebeak pacu, The species is endemic to rapids in the Xingu River basin in the Brazilian Amazon. This vulnerable species is primarily a herbivore.
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).
Myloplus schomburgkii, also known as the Disk tetra, Disk pacu, Black-ear pacu, Black-band myleus or Black-barred myleus is a species of serrasalmid with a black bar on its side. This species is found in the middle and lower Amazon River basin, Nanay River, upper Orinoco River basin in Brazil, Peru, Venezuela and possibly in Suriname.
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).
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.
Myleus is a genus of serrasalmids from South America, where found in the Amazon, Orinoco and São Francisco basins, as well as river basin of the Guiana Shield. They are found in rivers with moderately or fast-flowing water, including rapids. They are primarily herbivores, but also take some animal matter. Depending on the exact species, they reach up to 12–42 cm (0.4–1.4 ft) in standard length, and the adult males have a double-lobed anal fin and filamentous extensions on the dorsal fin. Their strong teeth means that larger individuals can inflict severe bites on humans.
Tometes is a genus of fish in the family Serrasalmidae found in fast-flowing rivers in northern South America. Adults of all seven species in this genus are phytophagous, feeding primarily on aquatic plants in the family Podostemaceae.
Utiaritichthys is a genus of serrasalmid fish found in the Amazon and Orinoco basins in tropical South America. The adults are typically found in rapidly flowing water where they feed on aquatic plants in the family Podostemaceae and filamentous algae. They reach up to 32.2 cm (1.06 ft) in standard length.
A clearwater river is classified based on its chemistry, sediments and water colour. Clearwater rivers have a low conductivity, relatively low levels of dissolved solids, typically have a neutral to slightly acidic pH and are very clear with a greenish colour. Clearwater rivers often have fast-flowing sections.
Myloplus nigrolineatus is a species of freshwater fish in the serrasalmid family of order Characiformes. It is native to the Amazon River basin in South America.
Myloplus lucienae is a medium to large omnivorous fish of the family Serrasalmidae from Brazil. It and can grow to a length of 33.8 cm (13.3 in).
Myloplus zorroi is a medium to large omnivorous fish of the family Serrasalmidae from Brazil.
Myloplus tumukumak is a medium to large omnivorous fish of the family Serrasalmidae from the Tumucumaque Mountain Range, in Brazil and French Guiana.
Bryconops durbinae, sometimes listed under the name Bryconops durbini, is a small species of freshwater fish in the family Iguanodectidae. It is the smallest species of the genus Bryconops. Like all members of Iguanodectidae, it inhabits rivers in the upper half of South America.
Bryconops florenceae is a small freshwater fish that inhabits the rivers of South America. Comprehensive research is lacking due to B. florenceae being the most recently described of the genus, but researchers believe it to be a relatively widespread species. It is found throughout the Maroni, Mana, and Sinnamary river basins, which defines its range within Suriname and French Guiana.
