Lungfish are freshwater vertebrates belonging to the class Dipnoi. Lungfish are best known for retaining ancestral characteristics within the Osteichthyes, including the ability to breathe air, and ancestral structures within Sarcopterygii, including the presence of lobed fins with a well-developed internal skeleton. Lungfish represent the closest living relatives of the tetrapods. The mouths of lungfish typically bear tooth plates, which are used to crush hard shelled organisms.
Gars are an ancient group of ray-finned fish in the family Lepisosteidae. They comprise seven living species of fish in two genera that inhabit fresh, brackish, and occasionally marine waters of eastern North America, Central America and Cuba in the Caribbean, though extinct members of the family were more widespread. They are the only surviving members of the Ginglymodi, a clade of fish which first appeared during the Triassic, over 240 million years ago, and are one of only two surviving groups of holosteian fish, alongside the bowfins, which have a similar 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.
Marine hatchetfishes or deep-sea hatchetfishes are small deep-sea mesopelagic ray-finned fish of the stomiiform subfamily Sternoptychinae. They should not be confused with the freshwater hatchetfishes, which are not particularly closely related Teleostei in the characiform family Gasteropelecidae.
Batrachoididae is the only family in the ray-finned fish order Batrachoidiformes. Members of this family are usually called toadfish or frogfish: both the English common name and scientific name refer to their toad-like appearance.
The tinfoil barb is a tropical Southeast Asian freshwater fish of the family Cyprinidae. This species was originally described as Barbus schwanenfeldii by Pieter Bleeker in 1853, and has also been placed in the genera Barbodes and Puntius. The specific epithet is frequently misspelled schwanefeldii.
The marine hatchetfishes or deep-sea hatchetfishes as well as the related bottlelights, pearlsides and constellationfishes are small deep-sea ray-finned fish of the stomiiform family Sternoptychidae. They are not closely related to and should not be confused with the freshwater hatchetfishes, which are teleosts in the characiform family Gasteropelecidae. The Sternoptychidae have 10 genera and about 70 species altogether.
The common hatchetfish or river hatchetfish is a tropical fish belonging to the freshwater hatchetfish family (Gasteropelecidae). Originating in South America in the Peruvian and middle Amazon, the Guianas and Venezuela, it grows to about 2.5 inches (6.4 cm). The fish gets its name from its relatively large protruding belly which resembles a hatchet. Hatchetfish will often jump out of the water when alarmed, propelled by their large, winglike pectoral fins. They also jump to catch small aerial insects.
The marbled hatchetfish is a small, normally 3.5 cm (1.4 in) in length, freshwater ray-finned fish native to South America. Hatchet shaped, it presents a gold line extending from its eye to its caudal fin while the area below has a brown and cream colored marble-like pattern.
Polypterus senegalus, commonly known as the Senegal bichir, gray bichir or Cuvier's bichir, is an African species of ray-finned fish in the bichir family, Polypteridae. It is a typical example of polypterid fishes, as most of its defining physical features are common across the genus, such as its ancient, lungfish- or arowana-like appearance, the ability to breathe atmospheric oxygen, and its armor-like scales. These factors have influenced the species' popularity in captivity, and it is commonly kept by aquarists and other hobbyists.
The channel catfish is North America's most numerous catfish species. It is the official fish of Kansas, Missouri, Nebraska, and Tennessee, and is informally referred to as a "channel cat". In the United States, they are the most fished catfish species with around 8 million anglers targeting them per year. They also have very few teeth and swallow food whole. The popularity of channel catfish for food has contributed to the rapid expansion of this species' aquaculture in the United States. Europe, Asia, and South America have also widely introduced it, and many countries legally consider it an invasive species.
The silver hatchetfish is a member of the genus Gasteropelecus in the family Gasteropelecidae. It is a relatively small fish that is often kept in aquariums. It is compressed laterally, with black and gold lines running along its side, adults will grow up to 3.5 cm in the wild and 6 cm in the aquarium.
The Aspredinidae are a small South American family of catfishes also known as the banjo catfishes, with about 43 species.
The freshwater butterflyfish or African butterflyfish is a species of osteoglossiform fish native to freshwater habitats in the Niger and Congo basins of western and central Africa. It is the only extant species in the family Pantodontidae. It is not closely related to saltwater butterflyfishes.
Frogfishes are any member of the anglerfish family Antennariidae, of the order Lophiiformes. Antennariids are known as anglerfish in Australia, where the term "frogfish" refers to members of the unrelated family Batrachoididae. Frogfishes are found in almost all tropical and subtropical oceans and seas around the world, the primary exception being the Mediterranean Sea.
The dwarf corydoras, dwarf catfish, tail spot pygmy catfish, or micro catfish is a tropical freshwater fish belonging to the subfamily Corydoradinae of the family Callichthyidae. It originates in inland waters in South America, and is found in the Amazon River and Paraguay River basins in Argentina, Bolivia, and Brazil. The specific epithet hastatus means with a spear, in reference to the spearhead-like spot on the tail root.
The emerald catfish is a tropical freshwater fish belonging to the Corydoradinae sub-family of the family Callichthyidae native to the Amazon Basin in South America. It has traditionally been known as Brochis splendens. The fish has appeared on a stamp in Brazil.
The snakeskin gourami is a species of gourami native to Southeast Asia. Prior to the merging of Belontidae to the family Osphronemidae, the snakeskin gourami was regarded as the largest member of its family. It is still the largest species in its genus and subfamily.
The black-winged hatchetfish is a freshwater ray-finned fish native to South America.
Thoracocharax stellatus, the silver hatchetfish, spotfin hatchetfish, spotted hatchetfish or platinum hatchetfish, is a widespread hatchetfish found throughout South America including Venezuela, Colombia, Ecuador, Brazil, Peru, Bolivia, Paraguay, and Argentina in the Amazon, Orinoco, Paraguay and Tocantins-Araguaia basins. This species is one of the largest of the hatchetfishes. It is usually found in areas with abundant riparian vegetation.
