Amblyopsidae

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Cavefishes

Northern cavefish, Amblyopsis spelaea

Scientific classification

Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Percopsiformes
Family:	Amblyopsidae

Genera

Amblyopsis
Chologaster
Forbesichthys
Speoplatyrhinus
Typhlichthys
See text for species.

The cavefishes (commonly: blindfishes, swampfishes) are found in caves and adapted to life in the dark, notably lacking eyes and pigmentation, as a result having a pale or whitish color. They are found all over the world. There are more than 80 known varieties of cavefish.

The blind and albinic cavefish Nemachielus evezardi from Kotumsar Cave, India

Cavefishes are generally small, ranging up to 2.5 cm in length. Most do not have pelvic fins, although Amblyopsis spelaea has small ones with up to six rays. Only three species of cave fish lack eyes completely, but several others have useless eyes. The majority of cave fish have little to no pigment in their skin. These features are an example of regressive evolution.

Cavefishes can only be found in caves that have streams running into them; a cave with no inlets (such as Blanchard Springs Caverns in Arkansas) will not contain cavefishes. They are believed to have been evolved from their aboveground counterparts.