The Mexican tetra, also known as the blind cave fish, blind cave characin or the blind cave tetra, is a freshwater fish in the Characidae family of the order Characiformes. The type species of its genus, it is native to the Nearctic realm, originating in the lower Rio Grande, and the Neueces and Pecos Rivers in Texas, into the Central Plateau and eastern states of Mexico.
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, 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.
Hagfish, of the class Myxini and order Myxiniformes, are eel-shaped jawless fish. Hagfish are the only known living animals that have a skull but no vertebral column, although they do have rudimentary vertebrae. Hagfish are marine predators and scavengers who can defend themselves against other larger predators by releasing copious amounts of slime from mucous glands in their skin.
Garra typhlops, also known as the Iran cave barb is a species of ray-finned fish in the family Cyprinidae. It is endemic to caves in Iran. Like other cave-adapted fish, it is blind and lacks pigmentation.
The blind cave eel is a species of cavefish in the family Synbranchidae. It is the longest cavefish in Australia and one of the only three vertebrates in Australia that is restricted to underground waters, the other being the blind gudgeon and the Barrow cave gudgeon. It is blind, its body is eel-like and elongated, and it has a non-pigmented skin with colours ranging from white to pink.
The blind swamp eel is a species of fish in the family Synbranchidae. It is endemic to Mexico where it lives in cave systems and is known in Spanish as the anguila ciega. The International Union for Conservation of Nature has rated this cavefish as "endangered".
Typhlichthys subterraneus, the southern cavefish, is a species of cavefish in the family Amblyopsidae endemic to karst regions of the eastern United States.
Leucopatus is a genus of velvet worm in the family Peripatopsidae, containing a single species, the blind velvet worm. It is found in northeast Tasmania, Australia, and is ovoviviparous.
Cavefish or cave fish is a generic term for fresh and brackish water fish adapted to life in caves and other underground habitats. Related terms are subterranean fish, troglomorphic fish, troglobitic fish, stygobitic fish, phreatic fish, and hypogean fish.
Phreatobius sanguijuela is a South American species of heptapterid catfish that lives in underground waters.
Lamprologus lethops is a species of cichlid fish from areas with fast current in the Congo River in Central Africa, where it is believed to live in depths as great as 160 m (520 ft) or 200 m (660 ft) below the surface. It reaches up to about 12.5 cm (5 in) in standard length, with females being somewhat smaller than males, is all whitish in color (non-pigmented), and essentially blind as adult, as their eyes are covered in a thick layer of skin. This is entirely unique among cichlids and an adaption to the perpetual darkness of its habitat, similar to the adaptions seen in cavefish. The eyes of juveniles are rudimentary and not covered by skin.
Amblyopinae is a subfamily of elongated mud-dwelling gobies commonly called eel gobies or worm gobies; it has been regarded as a subfamily of the family Gobiidae, while the 5th edition Fishes of the World classifies it as a subfamily of the family Oxudercidae. The members in the subfamily have two dorsal fins that are connected by a membranous structure and their eyes are highly reduced in size. They are usually pink, red, or purple in coloration.
Caecogobius cryptophthalmus is a species of goby that is endemic to underground habitats in Calbiga on the Philippine island of Samar. This species is one of two members of the genus Caecogobius. Like other cavefish, C. cryptophthalmus has reduced eyes and pigmentation.
