Amblyopsidae

The Amblyopsidae are a fish family commonly referred to as cavefish, blindfish, or swampfish. They are small freshwater fish found in the dark environments of caves (underground lakes, pools, rivers and streams), springs and swamps in the eastern half of the United States. Like other troglobites, most amblyopsids exhibit adaptations to these dark environments, including the lack of functional eyes and the absence of pigmentation. More than 200 species of cavefishes are known, but only six of these are in the family Amblyopsidae. One of these, Forbesichthys agassizii, spends time both underground and aboveground. A seventh species in this family, Chologaster cornuta, is not a cave-dweller but lives in aboveground swamps.

All members of this family are small and typical of the fresh waters of the eastern and southern regions of the United States. Some live deep in the swamps, and others in the lakes and streams or in caves, significantly the Kentucky cave system called the Mammoth caves.

Cavefish can only be found in caves that have streams running into them; a cave with no inlets does not contain cavefish.