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.
Osteoglossiformes is a relatively primitive order of ray-finned fish that contains two sub-orders, the Osteoglossoidei and the Notopteroidei. All of at least 245 living species inhabit freshwater. They are found in South America, Africa, Australia and southern Asia, having first evolved in Gondwana before that continent broke up. In 2008, several new species of marine osteoglossiforms were described from the Danish Eocene Fur Formation, dramatically increasing the diversity of this group. This implies that the Osteoglossomorpha is not a primary freshwater fish group with the osteoglossiforms having a typical Gondwana distribution.
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.
Gouramis, or gouramies, are a group of freshwater anabantiform fish that comprise the family Osphronemidae. The fish are native to Asia—from the Indian Subcontinent to Southeast Asia and northeasterly towards Korea. The name "gourami", of Indonesian origin, is also used for fish of the families Helostomatidae and Anabantidae.
Rasbora is a genus of fish in the family Cyprinidae. They are native to freshwater habitats in South and Southeast Asia, as well as southeast China. A single species, R. gerlachi, is only known from an old specimen that reputedly originated from Africa (Cameroon), but this locality is considered doubtful. They are small, up to 17 cm (6.7 in) long, although most species do not surpass 10 cm (4 in) and many have a dark horizontal stripe.
The family Notopteridae contains 10 species of osteoglossiform (bony-tongued) fishes, commonly known as featherbacks and knifefishes. These fishes live in freshwater or brackish environments in Africa and West South East and Southeast Asia.
Wallago attu, the Sareng catfish is a freshwater catfish of the family Siluridae, native to South and Southeast Asia. W. attu is found in large rivers and lakes in two geographically disconnected regions, with one population living over much of the Indian Subcontinent and the other in parts of Southeast Asia. This species can reach a length up to 1.1 m.
Kryptopterus is a genus of catfishes belonging to the family Siluridae. They are found in freshwater throughout Southeast Asia. The scientific name comes from Ancient Greek kryptós + ptéryx. It refers to the reduced or even entirely absent dorsal fin of these catfishes.
The African brown knifefish is the only species in the genus Xenomystus of the family Notopteridae. This fish is found in the Chad, Nile, Congo, Ogowe and Niger basins, as well as coastal river basins in Sierra Leone, Liberia, Togo, Benin and Cameroon.
The clown featherback, also known as the clown knifefish and spotted knifefish, is a nocturnal species of tropical fish with a long, knife-like body. This knifefish is native to freshwater habitats in Cambodia, China, Hong Kong, Laos, Macau, Thailand, and Vietnam, but it has also been introduced to regions outside its native range. It is one of the world's most invasive species.
The royal knifefish or Indochina featherback is a species of ray-finned fish in the family Notopteridae found in the Mekong basin in Cambodia, Laos, Thailand and Vietnam.
The flying fox is a Southeast Asian species of freshwater fish in the family Cyprinidae. It is commonly kept in the aquarium trade. Among other foods, it is known to eat green algae. It is sometimes mistakenly referred to as the Siamese algae eater.
The Siamese tigerfish, also known as the Siamese tiger perch, is a species of ray-finned fish belonging to the family Lobotidae, the tripletails and tiger perches. This fish is endemic to Indochina and is assessed as Critically Endangered by the IUCN.
The bronze featherback is a ray-finned fish in the family Notopteridae found in South and Southeast Asia. Although primarily found in fresh water, it has been known to enter brackish water. At present, it is the only member of the genus Notopterus, but as currently defined, it is likely a species complex.
Chitala chitala is a knifefish from Bangladesh, India, Nepal, and Pakistan, found in the Brahmaputra, Indus, Ganges and Mahanadi River basins. It is sometimes known as the Indian featherback or Indian knifefish. In the past, it frequently included several related Chitala species, but these are now regarded as separate species. The main species confused with this species is C. ornata ; a Southeast Asian species seen regularly in the aquarium trade. The true C. chitala is very rare in the aquarium trade.
The Indonesian featherback is a species of knifefish from freshwater habitats in Southeast Asia. The details of its range are not entirely clear, with FishBase reporting that it occurs in Sumatra, Borneo, and the Malay Peninsula, while Catalog of Fishes considers it endemic to Borneo.
Chitala lopis, also known as the belida or giant featherback, is a species of freshwater fish, endemic to the islands of Java and Sumatra in Indonesia. It inhabits lowland river mainstreams and tributaries with rocky and sunken wood bottoms, as well as forest-covered streams. It feeds on smaller fishes, insects and vertebrates, mostly at night. The species was declared to be extinct on 2020, but rediscovered at the type locality in 2023.
The reticulated knifefish is a species of freshwater fish in the family Notopteridae, the featherbacks, found in tropical West Africa. It reaches a maximum length of 80 cm (31 in) and a reported weight of 1.3 kg (2.9 lb).
