Devils Hole is the only natural habitat of the Devils Hole pupfish in Nevada. The water-filled cavern lies within a detached unit of Death Valley National Park, surrounded by Ash Meadows National Wildlife Refuge. Although the cavern extends deep underground, the fish depend mainly on a shallow rock shelf for feeding and spawning.
The species, Cyprinodon diabolis, is one of the world's rarest fish. It tolerates unusually warm, oxygen-poor water and has no pelvic fins. Its tiny habitat is especially vulnerable because groundwater withdrawals can lower the water level and expose the spawning shelf.
Devils Hole gained national protection in 1952, and the pupfish was listed as endangered in 1967. A landmark 1976 Supreme Court case, Cappaert v. United States, affirmed that groundwater needed to preserve the fish was protected along with the monument.
A common mix-up is Devils Hole Cave, a separate nearby cave system where no pupfish live. The fish's name and habitat both refer specifically to Devils Hole, not to a broad region or the nearby Amargosa River.