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.
These fish vary in length, though many are less than 3 cm (1.2 in). One of the smallest species, Hyphessobrycon roseus, grows to a maximum length of 1.9 cm.
These fish inhabit a wide range and a variety of habitats. They originate in the Americas, ranging from southwestern Texas and Mexico through Central and South America. Many of these fish come from rivers, but, for example, the blind cave tetra even inhabits caves.
|Red phantom tetras (Hyphessobrycon sweglesi)|
This family has undergone a large amount of systematic and taxonomic change. More recent revision has moved many former members of the family into their own related but distinct families – the pencilfishes of the genus Nannostomus are a typical example, having now been moved into the Lebiasinidae, the assorted predatory species belonging to Hoplias and Hoplerythrinus have now been moved into the Erythrinidae, and the sabre-toothed fishes of the genus Hydrolycus have been moved into the Cynodontidae. The former subfamily Alestiinae was promoted to family level (Alestiidae) and the subfamilies Crenuchinae and Characidiinae were moved to the family Crenuchidae.
Other fish families that were formerly classified as members of the Characidae, but which were moved into separate families of their own during recent taxonomic revisions (after 1994) include Acestrorhynchidae, Anostomidae, Chilodontidae, Citharinidae, Ctenoluciidae, Curimatidae, Distichodontidae, Gasteropelecidae, Hemiodontidae, Hepsetidae, Parodontidae, Prochilodontidae, Serrasalmidae, and Triporthidae.
The larger piranhas were originally classified as belonging to the Characidae, but various revisions place them in their own related family, the Serrasalmidae. This reassignment has yet to enjoy universal acceptance, but is gaining in popularity among taxonomists working with these fishes. Given the current state of flux of the Characidae, a number of other changes will doubtless take place, reassigning once-familiar species to other families. Indeed, the entire phylogeny of the Ostariophysi – fishes possessing a Weberian apparatus – has yet to be settled conclusively. Until that phylogeny is settled, the opportunity for yet more upheavals within the taxonomy of the characoid fishes is considerable.
|Phylogeny of Characidae from Melo et al. 2015 with clade names from van der Laan 2017.|
The subfamilies and tribes currently recognized by most if not all authors, and their respective genera, are:
Subfamily Spintherobolus clade
The Chalceidae, Iguanodectidae, Bryconidae and Heterocharacinae are the most recent clades to be removed in order to maintain a monophyletic Characidae.
Subfamily Iguanodectinae moved to Iguanodectidae
Subfamily Heterocharacinae moved to Acestrorhynchidae
Subfamily Bryconinae moved to Bryconidae
Subfamily Salmininae moved to Bryconidae
Genera incertae sedis
A large number of taxa in this family are incertae sedis. The relationships of many fish in this family – in particular species traditionally placed in the Tetragonopterinae, which had become something of a "wastebin taxon" – are poorly known, a comprehensive phylogenetic study for the entire family is needed. The genera Hyphessobrycon, Astyanax, Hemigrammus, Moenkhausia, and Bryconamericus include the largest number of currently recognized species among characid fishes that are in need of revision; Astyanax and Hyphessobrycon in the usual delimitation are among the largest genera in this family. These genera were originally proposed between 1854 and 1908 and are still more or less defined as by Carl H. Eigenmann in 1917, though diverse species have been added to each genus since that time. The anatomical diversity within each genus, the fact that each of these generic groups at the present time cannot be well-defined, and the high number of species involved are the major reasons for the lack of phylogenetic analyses dealing with the relationships of the species within these generic "groups".
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 (A. mexicanus) and this is supported by phylogenetic evidence, but others recognize the cave form as a separate species, A. jordani.The type species is A. argentatus, now regarded as a form of the Mexican tetra (A. mexicanus). The generic name comes from Astyanax, a character in Greek mythology, who was the son of Hector of Troy; in homage to this, several specific epithets also refer to the Iliad.Black phantom tetra
The black phantom tetra (Hyphessobrycon megalopterus), or simply phantom tetra, is a small freshwater fish of the characin family (Characidae) of order Characiformes. It is native to the upper Paraguay basin and upper Madeira basin (including Guaporé, Mamore and Beni) in Brazil and Bolivia. It is commonly seen in the aquarium trade.Brycinus
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.Like some other Alestiidae, they are called robber tetras due to their bold and rather carnivorous habits. They are not infrequently kept as aquarium fishes and in their requirements resemble the South American tetras of the Characidae. Unlike these, Brycinus are not well-suited to accompany delicate fishes however and are better kept with dwarf cichlids and similar small but robust companions.Brycon
Brycon is a genus of fish in the family Characidae found in freshwater habitats in Central and South America, ranging from southern Mexico to northern Argentina. Despite not being closely related to true trout, they are sometimes called South American trout. They reach a maximum length of 11.9–79.5 cm (4.7–31.3 in) depending on the species involved. Some species perform seasonal breeding migrations.They feed heavily on fruits and seeds, but also take other plant material, invertebrates and small fish. Their food is typically taken from the water, but they are able to jump out of the water to "pluck" low-hanging seeds and fruits directly from trees. Some seeds are crushed when eaten, but may also pass undamaged through the fish, making them seed dispersers.Brycon support important fisheries and based on a review by IBAMA, they are the fifth most caught fish by weight in the Brazilian Amazon.Characiformes
Characiformes is an order of ray-finned fish, comprising the characins and their allies. Grouped in 18 recognized families, there are more than two thousand different species, including the well-known piranha and tetras.Cheirodon
Cheirodon is a genus of characins occurring in South America. Of the 10 currently described species; one, C. jaguaribensis, is placed here as a convenience, as its actual position in Characidae is unknown.Hemigrammus
Hemigrammus is a genus of freshwater fish in the family Characidae native to South America (including Trinidad) and commonly seen in the aquarium trade. These are medium-small tetras where the largest species reach up to around 11 cm (4.3 in).Hemigrammus pulcher
Hemigrammus pulcher is a semi-popular aquarium species, also known as the pretty tetra, garnet tetra or black wedge tetra. In the wild, the species is found near Iquitos in the Peruvian Amazon, and probably also in Brazil and Colombia.Hyphessobrycon
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 Neotropic ecozone from southern Mexico to Río de la Plata in Argentina. Many of these species are native to South America; about half a dozen species are from Central America and a single species, H. compressus is from southern Mexico.All small fishes, the Hyphessobrycon tetras reach maximum overall lengths of about 1.7–9.6 cm (0.7–3.8 in). There is great anatomical diversity in this genus. They are generally of typical characin shape, but vary greatly in coloration and body form, many species having distinctive black, red or yellow markings on their bodies and fins. These species are generally omnivorous, feeding predominantly on small crustaceans, insects, annelid worms and zooplankton. When spawning, they scatter their eggs and guard neither eggs nor young.Lepidophagy
Lepidophagy is a specialised feeding behaviour in fish that involves eating of scales of other fish. Lepidophagy is widespread, having been independently evolved in at least five freshwater families and seven marine families. A related feeding behavior is pterygophagy, which are fish that feed on the fins of other fish.Lepidophagy has been reported in a range of fish including: Chanda nama (family Ambassidae), Plagiotremus (family Blenniidae), Terapon jarbua (family Terapontidae), a few Ariopsis and Neoarius species (family Ariidae), several pencil catfish (family Trichomycteridae), some piranha, Exodon paradoxus, Probolodus, Roeboides and Roeboexodon species (order Characiformes), along with both Perissodus species, all four Plecodus species, Xenochromis, Haplochromis welcommei, Docimodus, Corematodus and Genyochromis mento (family Cichlidae from the African Great Lakes).Several of these scale-eaters will also feed on fins of other fish and many omnivorous or predatory fish may on occasion nip the fins of other fish. Only a few are specialized fin-eaters, notably Belonophago, Eugnathichthys and Phago (family Distichodontidae), Aspidontus (family Blenniidae), and Smilosicyopus (family Gobiidae). A somewhat related behavior is found in Magosternarchus, which feed on the tails (both fin and connective tissue) of other gymnotiform knifefish.Mimagoniates microlepis
Mimagoniates microlepis, also known as the blue tetra (a common name shared with Tyttocharax madeirae, Knodus borki, and possibly other Characidae, as well), the croaking tetra (a name also applied to Mimagoniates inequalis and Mimagoniates lateralis), 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 (Miranda-Ribeiro, 1908), Coelurichthys lateralis, and Mimagoniates iporangae (McAllister, 1990) besides its current taxonomic classification. There is evidence of a variety called M. microlepis 'Joinville' which might be synonymous with Paragoniates microlepis.Moenkhausia
Moenkhausia is a genus of freshwater fish in the family Characidae native to tropical and subtropical South America. These are medium-sized tetras where the largest species only reach around 12 cm (4.7 in).The diamond tetra and red-eye tetra, which are commonly kept in aquaria, are members of this genus.Nematobrycon palmeri
Nematobrycon palmeri, commonly known as the emperor tetra, is a species of characid fish found in the Atrato and San Juan river basins in western Colombia. It was first imported in the aquarium trade to the United States in 1960 and has since become well established.Paracheirodon
Paracheirodon is a genus of freshwater fish in the family Characidae of the order Characiformes. The type species is P. innesi, the well-known neon tetra, and the Paracheirodon species are among the fishes known as tetras. All species of this genus are native to the Neotropic ecozone, occurring in the Orinoco and Amazon Basins in northern South America.
Paracheirodon tetras reach maximum overall lengths of 2.5 to 5 cm (0.98 to 1.97 in) depending on the species, and are of elongated, tetra shapes. All share a distinctive iridescent blue lateral line, but differ slightly in their other colorations.
Preferring soft, acidic waters, these midwater shoaling fishes feed predominantly on small crustaceans, insects, worms, and zooplankton. When spawning, they scatter their eggs and guard neither eggs nor young.
The generic name Paracheirodon derives from the Ancient Greek χείρ (hand), and οδών (teeth), prefixed with παρά (beside) to distinguish it from the similar characin genus Cheirodon.Piranha
A piranha or piraña (, , or ; Portuguese: [piˈɾɐ̃ɲɐ], Spanish: [piˈɾaɲa]), a member of family Characidae in order Characiformes, is a freshwater fish that inhabits South American rivers, floodplains, lakes and reservoirs. Although often described as extremely predatory and mainly feeding on fish, their dietary habits vary extensively, and they will also take plant material, leading to their classification as omnivorous. In Venezuela, they are called caribes. They are known for their sharp teeth and powerful jaws.Pristella maxillaris
Pristella maxillaris, the only species in the genus Pristella, is commonly known as the X-ray fish or X-ray tetra because of its translucent body. It is a widely distributed and adaptable fish, found in the Amazon and Orinoco basins, as well as coastal rivers in the Guianas in both acidic and alkaline waters. Unlike most other characins, it is tolerant of (and sometimes found in) slightly brackish water. It is small (up to around 5 cm or 2.0 in in length) and lives in large groups, and males can be distinguished from females by being smaller and thinner than the females. Like most other tetras, it feeds primarily on small insects and planktonic animals.Salminus
Salminus, popularly known as dorado or dourado, is a genus of relatively large (up to 1.3–1.4 m or 4.3–4.6 ft long), predatory freshwater fish from the Characidae family. They are native to large tropical and subtropical rivers in South America, and undertake migrations during the rainy season to spawn. They are very popular among recreational anglers and also support important commercial fisheries.Tetra
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 (the "African tetras") 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 (Paracheirodon innesi), are brightly colored and easy to keep in captivity. Consequently, they are extremely popular for home aquaria.
Tetra is no longer a taxonomic, phylogenetic term. It is short for Tetragonopterus, a genus name formerly applied to many of these fish, which is Greek for "square-finned" (literally, four-sided-wing).
Because of the popularity of tetras in the fishkeeping hobby, many unrelated fish are commonly known as tetras, including species from different families. Even vastly different fish may be called tetras. For example, payara (Hydrolycus scomberoides) is occasionally known as the "sabretooth tetra" or "vampire tetra".
Tetras generally have compressed (sometimes deep), fusiform bodies and are typically identifiable by their fins. They ordinarily possess a homocercal caudal fin (a twin-lobed, or forked, tail fin whose upper and lower lobes are of equal size) and a tall dorsal fin characterized by a short connection to the fish’s body. Additionally, tetras possess a long anal fin stretching from a position just posterior of the dorsal fin and ending on the ventral caudal peduncle, and a small, fleshy adipose fin located dorsally between the dorsal and caudal fins. This adipose fin represents the fourth unpaired fin on the fish (the four unpaired fins are the caudal fin, dorsal fin, anal fin, and adipose fin), lending to the name tetra, which is Greek for four. While this adipose fin is generally considered the distinguishing feature, some tetras (such as the emperor tetras, Nematobrycon palmeri) lack this appendage. Ichthyologists debate the function of the adipose fin, doubting its role in swimming due to its small size and lack of stiffening rays or spines.Although the list below is sorted by common name, in a number of cases the common name is applied to different species. Since the aquarium trade may use a different name for the same species, advanced aquarists tend to use scientific names for the less-common tetras. The list below is incomplete.Thayeria boehlkei
Thayeria boehlkei is a species of characin fish endemic to the Amazon river basin and Araguaia river, in Peru and Brazil respectively. The species is popular with aquarium hobbyists where it is traded under a variety of common names including blackline penguinfish, blackline thayeria, hockey-stick tetra, penguin fish and penguin tetra.