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 mata mata, mata-mata, or matamata is a South American species of freshwater turtle found in the Amazon basin and river system of the eastern Guianas. It was formerly believed to also occur in the Orinoco basin, western Guianas and upper Rio Negro–Branco system, but in 2020 these populations were found to belong to a separate species, Chelus orinocensis. Subsequently, some authorities have modified the common name of Chelus fimbriata to Amazon mata mata. These two are the only extant species in the genus Chelus.
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, is a large species of South American pimelodid (long-whiskered) catfish. It is known in Venezuelan Spanish as cajaro; in Guyana, it is known as a banana catfish, and in Brazil it is known as pirarara, a fusion of words from the indigenous Tupi language: pirá and arara. It is the only extant species of its genus, Phractocephalus.
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.
The smooth-fronted caiman, also known as Schneider's dwarf caiman or Schneider's smooth-fronted caiman, is a crocodilian from South America, where it is native to the Amazon and Orinoco Basins. It is the second-smallest species of the family Alligatoridae, the smallest being Cuvier's dwarf caiman, also from tropical South America and in the same genus. An adult typically grows to around 1.2 to 1.6 m in length and weighs between 9 and 20 kg. Exceptionally large males can reach as much as 2.3 m (7.5 ft) in length and 36 kg (79 lb) in weight.
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.
Cichla temensis, the speckled peacock bass, painted pavon, royal pavon, speckled pavon, three-barred peacock bass, or striped tucunare, is a very large South American cichlid. Reaching nearly 1 m (3.3 ft) in length, it is the largest cichlid of the Americas, and one of the largest extant cichlids in the world. It is an important predator in its native waterways, as well as a prized food fish and game fish, which has led to a number of attempted introductions outside of its native range.
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 harm, or payara, a name it shares with the related H. scomberoides.
