The Amazon river dolphin, also known as the boto, bufeo or pink river dolphin, is a species of toothed whale endemic to South America and is classified in the family Iniidae. Three subspecies are currently recognized: I. g. geoffrensis, I. g. boliviensis and I. g. humboldtiana while position of Araguaian river dolphin within the clade is still unclear. The three subspecies are distributed in the Amazon basin, the upper Madeira River in Bolivia, and the Orinoco basin, respectively.
The ghost knifefishes are a family, Apteronotidae, of ray-finned fishes in the order Gymnotiformes. These fish are native to Panama and South America. They inhabit a wide range of freshwater habitats, but more than half the species in the family are found deep in rivers where there is little or no light.
Arowanas are freshwater bony fish of the subfamily Osteoglossinae, also known as bony tongues. In this family of fish, the head is bony and the elongated body is covered by large, heavy scales, with a mosaic pattern of canals. The dorsal and anal fins have soft rays and are long based, while the pectoral and ventral fins are small. The name "bonytongues" is derived from a toothed bone on the floor of the mouth, the "tongue", equipped with teeth that bite against teeth on the roof of the mouth. The arowana is a facultative air breather and can obtain oxygen from air by sucking it into its swim bladder, which is lined with capillaries like lung tissue.
The silver arowana is a South American freshwater bony fish of the family Osteoglossidae. Silver arowanas are sometimes kept in aquariums, but they are predatory and require a very large tank.
The Asian arowana comprises several phenotypic varieties of freshwater fish distributed geographically across Southeast Asia. While most consider the different varieties to belong to a single species, work by Pouyaud et al. (2003) differentiates these varieties into multiple species. They have several other common names, including Asian bonytongue, dragonfish, and a number of names specific to the different color varieties.
Peacock bass or Brazilian tucunaré are large freshwater cichlids of the genus Cichla. These are diurnal predatory fishes native to the Amazon and Orinoco basins, as well as rivers of the Guianas, in tropical South America. They are sometimes referred to in English by their Brazilian name tucunaré or their Spanish name pavon. Despite the common name and their superficial similarity, they are not closely related to other fish known as bass, such as the North American largemouth bass.
Osteoglossum is a genus of fish in the family Osteoglossidae. They reach about 1 m (3.3 ft) in length and are restricted to freshwater habitats in tropical South America.
The redtail catfish, Phractocephalus hemioliopterus, is a pimelodid (long-whiskered) catfish. In Venezuela, it is known as cajaro, in Guyana, it is known as a banana catfish, and in Brazil, it is known as pirarara, stemming from the Tupi language words pirá and arara. It is the only extant species of the genus Phractocephalus. This fish is common in the aquarium trade, although its massive adult size makes it unsuitable for all but the largest aquariums. They feed on fish, crustaceans and fallen fruits. They are not evaluated by IUCN.
Astronotus is a genus of South American fish from the family Cichlidae. There are two commonly recognized species in the genus, though genetic evidence suggests that additional species exist; several of these possibly distinct populations also have very different juvenile coloration from the two recognized species. Both of the commonly recognized species are found in the Amazon Basin, while one of two also is found in the Paraná and Paraguay rivers. Astronotus species grow to 35 cm in size, and are monomorphic. They are opportunistic omnivores and consume a range of smaller fish, fruits, nuts, crustaceans, mollusks and other invertebrates in the wild.
Symphysodon aequifasciatus, the blue discus or brown discus, is a species of cichlid native to rivers of the eastern and central Amazon Basin downriver from the Purus Arch. This discus is found in black-, clear- and whitewater, but its preference for lentic habitats such as floodplains and flooded forests means that the whitewater it inhabits contain little suspended material. It is largely restricted to water with a high temperature of 25–32 °C (77–90 °F) and a pH of 5.2–7.7.
Sorubim is a small genus of long-whiskered catfish native to tropical South America. A number of characteristics allows the differentiation of each species in the genus. Sorubim species are important food fish in South America and are highly significant to fisheries of some areas; however, harvests of these fish are not identified as much as other, more popular food fishes such as Colossoma, Arapaima, and Brachyplatystoma. Some species of this family are popular aquarium fish.
Hemiancistrus is a genus of suckermouth armored catfishes. These species are native to South America. The taxonomy of this genus is complex and unclear, and major work has to be done. Many of these fish are popular aquarium fish.
Alexandre Rodrigues Ferreira was a Portuguese naturalist born in Brazil. He undertook an extensive journey which crossed the interior of the Amazon Basin to Mato Grosso, between 1783 and 1792. During this journey, he described the agriculture, flora, fauna, and native inhabitants.
Asterophysus batrachus, the gulper catfish or ogre catfish, is a species of catfish of the family Auchenipteridae. It is native to the Rio Negro and Orinoco basins in Brazil, Colombia and Venezuela, where mostly found in slow-moving waters with many submerged structures. It is currently the only recognized species of the genus Asterophysus, but a specimen that possibly represents an undescribed species has been collected in Marajó.
Apteronotus is a genus of weakly electric knifefish in the family Apteronotidae, distinguished by the presence of a tiny tail fin. This genus is restricted to tropical and subtropical South America and Panama where found in a wide range of freshwater habitats. They feed on small animals.
The biara is a South American piscivorous fish in the dogtooth characin family. It belongs to the monotypic genus Rhaphiodon, although some minor differences in morphometrics and colour are known from across its large range. It is found in the Amazon, Orinoco, and Río de la Plata Basins, as well as rivers of the Guianas. It occurs in a wide range of freshwater habitats such as main river channels, flooded forests, lakes and reservoirs. Some populations are migratory.
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.
Piaractus is a genus of large serrasalmid from South America. The two traditionally recognized species of Piaractus are very similar in appearance and were formerly included in the genus Colossoma, which currently only contains another similar species, the tambaqui. A third Piaractus was described in 2019 as a new species, but it was formerly considered a subpopulation of P. brachypomus.
Arapaiminae is a subfamily of freshwater osteoglossiform (bony-tongued) fishes belonging to the family Osteoglossidae. It includes the South American arapaimas of the Amazon and Essequibo basins and the African arowana from the watersheds of the Sahelo-Sudanese region, Senegal, Gambia, and parts of Eastern Africa. This subfamily is sometimes raised to the rank of family, as Arapaimidae. A commonly used synonym is Heterotidinae, but according to the ICZN, Arapaiminae has priority.
Hydrolycus armatus is a species of dogtooth characin found in freshwater of tropical South America. It is sometimes known as the payara, a name it shares with the related H. scomberoides.
