Characidae, the characids or characins is a family of freshwater subtropical and tropical fish, belonging to the order Characiformes. The name "characins" is the historical one, but scientists today tend to prefer "characids" to reflect their status as a by and large monophyletic group at family rank. To arrive there, this family has undergone much systematic and taxonomic change. Among those fishes that remain in the Characidae for the time being are the tetras, comprising the very similar genera Hemigrammus and Hyphessobrycon, as well as a few related forms such as the cave and neon tetras. Fish of this family are important as food and also include popular aquarium fish species.
Tetra is the common name of many small freshwater characiform fishes. Tetras come from Africa, Central America, and South America, belonging to the biological family Characidae and to its former subfamilies Alestidae and Lebiasinidae. The Characidae are distinguished from other fish by the presence of a small adipose fin between the dorsal and caudal fins. Many of these, such as the neon tetra, are brightly colored and easy to keep in captivity. Consequently, they are extremely popular for home aquaria.
Arapaima gigas, also known as pirarucu or simply arapaima, is a species of arapaima native to the basin of the Amazon River. Once believed to be the sole species in the genus, it is among the largest freshwater fish. The species is an obligate air-breather, so needs to come to the surface regularly to gulp air.
Hydrophilidae, also known colloquially as water scavenger beetles, is a family of beetles. Aquatic hydrophilids are notable for their long maxillary palps, which are longer than their antennae. Several of the former subfamilies of Hydrophilidae have recently been removed and elevated to family rank; Epimetopidae, Georissidae, Helophoridae, Hydrochidae, and Spercheidae. While the majority of hydrophilids are aquatic, around a third of described species are terrestrial, mostly belonging to the subfamily Sphaeridiinae.
Hyphessobrycon is a genus of freshwater fish in the family Characidae. These species are among the fishes known as tetras. The genus is distributed in the Neotropical realm from southern Mexico to Río de la Plata in Argentina. Many of these species are native to South America; about six species are from Central America and a single species, H. compressus is from southern Mexico.
Astyanax is a genus of freshwater fish in the family Characidae of the order Characiformes. Some of these fish, like many of their relatives, are kept as aquarium pets and known collectively as tetras. With around 150 described species and new ones being described yearly, this genus is among the largest of the entire order; Hyphessobrycon also has more than 145 species and which one is larger at any one time depends on whether more species have been recently described in one or the other. The blind and colorless cave tetra of Mexico is a famous member of the genus, but its taxonomic position is disputed: Some recognize it as part of the Mexican tetra and this is supported by phylogenetic evidence, but others recognize the cave form as a separate species, A. jordani.
Nannostomus is a genus of fish belonging to the characin family Lebiasinidae. All of the species in this genus are known as pencil fish, a popular name that was initially only applied to two species in the 1920s, Nannostomus unifasciatus and Nannostomus eques, by the late 1950s however, the term would be applied to all members of the genus. Several species have become popular aquarium fish due to their attractive coloration, unique shape, and interesting demeanor.
The croaking gourami is a species of small freshwater labyrinth fish of the gourami family. They are native to still waters in Southeast Asia and are distributed worldwide via the aquarium trade. Croaking gouramis are capable of producing a "croaking" noise using their pectoral fins.
Glandulocaudinae are a subfamily of tropical freshwater characin fish from Central and South America. In all species of this subfamily, a gland on their caudal fin is found almost exclusively in the males, which allows the release and pumping of pheromones; also, members of this subfamily have complex courtship behaviors which lead to insemination. The ecology and life history of these fish is complex yet little studied. Glandulocaudines are important as food fish for larger fish important for commercial and subsistence reasons.
Brycinus is a genus of ray-finned fish in the family Alestiidae. Like other "African characids", they were formerly included in the Characidae but are actually somewhat more distantly related Characiformes.
Stygichthys typhlops, the blind tetra or Brazilian blind characid, is a species of fish in the family Characidae and the only member of the genus Stygichthys. It is endemic to caves in northern Minas Gerais, Brazil. Like other cave-adapted fish, the Brazilian blind characid is blind and lacks pigmentation. It reaches up to about 4.6 cm (1.8 in) in standard length. It is solitary and when kept together in an aquarium, individuals are indifferent to each other.
Cavefish or cave fish is a generic term for fresh and brackish water fish adapted to life in caves and other underground habitats. Related terms are subterranean fish, troglomorphic fish, troglobitic fish, stygobitic fish, phreatic fish and hypogean fish.
Mimagoniates microlepis, also known as the blue tetra, the croaking tetra, the small-scaled tetra, is a species of tetra in the genus Mimagoniates. First identified by Franz Steindachner in 1876 and named Coelurichthys microlepis, it has also been identified as Coelurichthys iporangae, Coelurichthys lateralis, and Mimagoniates iporangae besides its current taxonomic classification. There is evidence of a variety called M. microlepis 'Joinville' which might be synonymous with Paragoniates microlepis.
Mimagoniates lateralis is a species of tetra in the genus Mimagoniates. Its common names include croaking tetra.
Mimagoniates inequalis, known as the croaking tetra, is a species of tetra in the genus Mimagoniates. It was previously classified as Glandulocauda inequalis
Glandulocauda is a genus of small characin freshwater fish that are endemic to Brazil, where restricted to the upper Paraná basin and coastal river basins in São Paulo state. The genus it is closely related to Lophiobrycon and Mimagoniates, and they form the tribe Glandulocaudini.
Hysteronotus megalostomus is a species of characin endemic to Brazil where it is found in the upper São Francisco River basin. This species is the only member of the genus Hysteronotus.
Knodus is a genus of characins, small freshwater fish from South America.
Lophiobrycon weitzmani is a species of small characin endemic to Brazil, where it is found in the upper Paraná River basin. It is considered threatened by Brazil's Ministry of the Environment. This species is the only member of the genus Lophiobrycon, but it is closely related to Glandulocauda and Mimagoniates.
Planaltina is a genus of characins endemic to Brazil.
