''Astyanax'' is a genus of

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

fish in the family

Characidae 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 st ...

of the

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

Characiformes. Some of these fish, like many of their relatives, are kept as

aquarium An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...

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 Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

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 Generic or generics may refer to: In business * Generic term, a common name used for a range or class of similar things not protected by trademark * Generic brand, a brand for a product that does not have an associated brand or trademark, other ...

name comes from Astyanax, a character in Greek mythology, who was the son of

Hector of Troy In Greek mythology, Hector (; grc, Ἕκτωρ, Hektōr, label=none, ) is a character in Homer's Iliad. He was a Trojan prince and the greatest warrior for Troy during the Trojan War. Hector led the Trojans and their allies in the defense o ...

; in homage to this, several

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

s also refer to the '' Iliad''.

Taxonomy and systematics

This genus is more or less defined as in 1917 by

Carl H. Eigenmann Carl Henry Eigenmann (March 9, 1863 – April 24, 1927) was a German-American ichthyologist of the late nineteenth and early twentieth centuries, who, along with his wife Rosa Smith Eigenmann, and his zoology students is credited with identifyin ...

. The lack of comprehensive phylogenetic analyses dealing with this genus is hindering a thorough review and the relationships remain as indeterminate as the monophyly is doubtful. The results of 2020 study using a combination of molecular and morphological data appeared to confirm that ''Astyanax'' is not monophyletic and suggested the creation of two new genera and the resurrection of '' Psalidodon''. Although included in ''Astyanax'' by

FishBase FishBase is a global species database of fish species (specifically finfish). It is the largest and most extensively accessed online database on adult finfish on the web.

, phylogenetic evidence supports moving ''A. aurocaudatus'' back to the monotypic genus '' Carlastyanax''.

Species

There are currently 147 recognized species in this genus:

References

{{DEFAULTSORT:Astyanax (Fish) Tetras Taxa named by Spencer Fullerton Baird Taxa named by Charles Frédéric Girard