A critically endangered type of cavefish which lives in underground pools in Key Cave, located in northwestern Alabama, United States in the Key Cave National Wildlife Refuge. This is the only known location of the fish, and was discovered underneath a colony of grey Bats in 1974 by Cooper and Kuehne.

Only nine specimens of the cavefish have been observed and scientists estimate that fewer than 100 are left on the planet. It is believed that this fish is the rarest of American cavefish and one of the rarest of all freshwater fish. It is the most specialised cavefish known, and exists in a fragile ecosystem based on nutrient rich guano of the grey bat. Researchers have failed to find the fish living in any other location.

The Alabama cavefish is a typical troglobite.

The Alabama cavefish is one of the rarest troglobitic fish species in North America. When this species was discovered in 1970, it was so unusual that a new genus was created for its description (Cooper and Kuehne, 1974). The species is restricted to Key Cave in Lauderdale County, Alabama with only nine specimens having been collected. Because the underground water system in the area is so widespread, it was hoped that the cavefish had dispersed to other sites. However, studies of 120 other caves in the area, conducted since 1977, have failed to locate any other cavefish populations. The number of individuals in the Key Cave population is estimated to be less than 100. In 1988 the Alabama cavefish was reclassified from "threatened" to "endangered". There are two unconfirmed reports that these fish have also been seen in nearby Collier Cave. Both caves are protected and inaccessible to the public.

Its longevity ranges from 5 to 10 years, but it reproduces slower than all other cave dwellers. Because its known range is limited to a single cave, the Alabama cavefish has an uncertain future, being threatened by changes in groundwater quality and level, changes in aquifer characteristics, diminished organic input. It also may compete with the syntopic southern cavefish, Typhlichthys subterraneus.

The average Alabama cavefish is about 3 inches (7.6 cm) long and has no eyes or discernible pigmentation, appearing semi-transparent with a slight pink hue. Its large head makes up more than one-third of its length. It is the only species in its genus, and can be distinguished from other cavefish with its very elongated, flattened head with a laterally constricted snout and a terminal mouth. The cavefish lacks pelvic fins, and its fin rays are unbranched with the fin membranes deeply incised between the rays. It has an elaborate system of sensory papillae, arranged in ridges on the head and sides, that is an adaptation to the dark environment.