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Mexican tetra

Mexican tetra
Astyanax mexicanus.JPG
Mexican tetra, normal form and blind cave fish
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Characiformes
Family: Characidae
Genus: Astyanax
Species: A. mexicanus
Binomial name
Astyanax mexicanus
(De Filippi, 1853)
Synonyms
  • Tetragonopterus mexicanus De Filippi, 1853
  • Astyanax fasciatus mexicanus (De Filippi, 1853)
  • Astyanax argentatus Baird & Girard, 1854
  • Tetragonopterus brevimanus Günther, 1864
  • Tetragonopterus petenensis Günther, 1864
  • Tetragonopterus fulgens Bocourt, 1868
  • Tetragonopterus nitidus Bocourt, 1868
  • Tetragonopterus streetsii Cope, 1872

The Mexican tetra or blind cave fish (Astyanax mexicanus) is a freshwater fish of the family Characidae of the order Characiformes. The type species of its genus, it is native to the Nearctic ecozone, originating in the lower Rio Grande and the Neueces and Pecos Rivers in Texas, as well as the central and eastern parts of Mexico.

Growing to a maximum overall length of 12 cm (4.7 in), the Mexican tetra is of typical characin shape, with unremarkable, drab coloration. Its blind cave form, however, is notable for having no eyes and being albino, that is, completely devoid of pigmentation; it has a pinkish-white color to its body.

This fish, especially the blind variant, is reasonably popular among aquarists.

A. mexicanus is a peaceful species that spends most of its time in midlevel water above the rocky and sandy bottoms of pools and backwaters of creeks and rivers of its native environment. Coming from a subtropical climate, it prefers water with 6.0–7.8 pH, a hardness of up to 30 dGH, and a temperature range of 20 to 25 °C (68 to 77 °F). In the winter, it migrates to warmer waters. Its natural diet consists of crustaceans, insects, and annelids, although in captivity it is omnivorous.

The Mexican tetra has been treated as a subspecies of A. fasciatus, but this is not widely accepted.


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Wikipedia

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