Pacu is a common name used to refer to several species of omnivorous South American freshwater serrasalmid fish related to the piranha. Pacu and piranha do not have similar teeth, the main difference being jaw alignment; piranha have pointed, razor-sharp teeth in a pronounced underbite, whereas pacu have squarer, straighter teeth and a less severe underbite, or a slight overbite. Pacu, unlike piranha, mainly feed on plant material and not flesh or scales. Additionally, the pacu can reach much larger sizes than piranha, at up to 1.08 m in total length and 40 kg (88 lb) in weight.
Serrasalmus geryi, known as the violet line piranha or Gery's piranha, is a species of piranha of the family Serrasalmidae. It is found in the lower Tocantins and Araguaia Rivers of Brazil. The species is notable for being the one of only the members of the genus Serrasalmus that can coexist with others of the same species in captivity, however caution is advised. Gery's Piranha reaches sizes up to 12 inches in length. As of 2018, it is classified as Least Concern by the International Union for Conservation of Nature.
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.
Teleocichla is a genus of fish in the family Cichlidae found in the Tapajós, Xingu, Tocantins and Jari River basins, which are part of the Amazon River Basin in Brazil. All species are rheophilic, and highly elongated in shape. They generally are smaller than 9 cm (3.5 in) in length, making them some of the smallest cichlids of the Americas. Only T. preta can grow larger, reaching about 12 cm (4.7 in). Since restricted to areas with fast currents, they are particularly vulnerable to the building of dams, and the Belo Monte Dam may cause the extinction of T. centisquama. Other species recognized as threatened by Brazil's Ministry of the Environment are T. cinderella, T. prionogenys and T. wajapi.
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.
Mylesinus is a genus of serrasalmids from South America, where found in the eastern Amazon, Essequibo and Orinoco basins. They are rheophilic, typically found at rapids and mainly feed on Podostemaceae plants. Because of their habitat preference, they are threatened by the building of dams. They reach up to 35 cm (1.15 ft) in standard length, and the adult males have a double-lobed anal fin and several filamentous extensions on the dorsal fin.
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.
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.
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.
Hoplias curupira, also known as the black wolf-fish, has a wide distribution in the Amazon basin but was described as recently as 2009.
Mylossoma duriventre, the silver mylossoma, is a species of freshwater serrasalmid fish endemic to tropical and subtropical South America. It grows to a maximum length of about 25 cm (10 in) and a weight of 1 kg (2.2 lb). It is the subject of a local fishery, being known as 'pacu' in Brazil and 'palometa' in Venezuela.
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 arnoldi is a medium to large omnivorous fish of the family Serrasalmidae from South America, where it is found in the Amazon, Xingu and Tocantins River basins. It can grow to a length of 33 cm (13 in). They are also called the silver dollar and are one of the fish referred to as "silver dollars". These fish are capable of delivering serious bites to humans.
Myloplus asterias is a medium to large omnivorous fish of the family Serrasalmidae from South America, where found in the Amazon River basin, as well as the north and the eastern Guiana Shield rivers. It and can grow to a length of 25 cm (9.8 in).
Myloplus levis is a medium to large omnivorous fish of the family Serrasalmidae from South America, where found in the Paraguay-Paraná River basin. It and can grow to a length of 20 cm (7.9 in).
Myloplus lobatus is a medium to large omnivorous fish of the family Serrasalmidae from South America, where found in the Amazon and Orinoco River basins. It and can grow to a length of 24 cm (9.4 in).
Acnodon normani, the sheep-pacu, is a species of serrasalmids found in South America. It is found in the Amazon, the Xingu and Tocantins River basins in Brazil. This species reaches a length of 19.9 cm (7.8 in).
Acnodon senai is a species of serrasalmids found in South America. It is found in the Jari River basin in Brazil. This species reaches a length of 13.2 cm (5.2 in).
Myloplus tiete, is a medium to large omnivorous fish of the family Serrasalmidae from South America, where found in the Paraguay-Paraná River basin. It and can grow to a length of 16.3 cm (6.4 in).
Bryconops rheoruber is a species of freshwater fish from the rivers of Brazil. Its back scales are tan-to-cream, and its belly is silvery; the divide between the two colors is marked by a broad iridescent-silver stripe. Its fins are a mixture of pale, clear, and reddish, which contributed to its specific name. "Rheo" means "flow" or "current" in Greek, and "ruber" means "red" in Latin.
