Scientists have discovered a new species of colorless, blind fish living in caves beneath a contaminated U.S. military base in Alabama.
Biologists have named these creatures the "devilish cavefish" (Demogorgonichthys arcanus) after the terrifying monster Demogorgon in the popular Netflix series Stranger Things, as well as the legendary demon in Greek mythology from which the name is derived.
The discovery was made by chance in early 2025, when Dr. Matthew Niemeller of the University of Alabama was conducting a routine survey of the "Bobcat" cave, located within the "Redstone Arsenal" military base, which was a center for the production of chemical weapons during World War II.
Niemeller slipped into the mud and fell into a pool of water, where he discovered a fish and a crab under a rocky ledge, and took pictures of them before the mud obscured the view.
Days later, Niemler noticed from the photographs that the fish differed from the known southern cavefish of the region, possessing a hump behind its head, a long, flattened snout, and unbranched fin rays. Upon returning a few days later, the team confirmed that nearly half of the cavefish they had observed belonged to this new species.
Genetic analysis revealed that this fish does not belong to any known group of cavefish and carries unique gene mutations that disrupt the rhodopsin protein responsible for vision in dim light. This suggests that the fish lost its sight independently of its neighboring species, an example of convergent evolution where organisms living in similar environments develop similar characteristics.
The cave's conditions were shaped by the contaminated history of the military base, which manufactured chemical weapons during World War II and buried large quantities of chemical munitions, including mustard gas (sulfur sulfide) and nerve agents (or nerve gases such as sarin, tabun, and soman) recovered from Nazi Germany. The site continues to undergo cleanup operations, and scientists have found elevated levels of trace metals in the cave's water.
But the biggest concern is that surface water connected to the cave carries pollutants and runoff from the nearby city of Huntsville. Because this fish lives in only one cave, it is critically endangered, and scientists have concluded that it meets the criteria for "endangered" on the IUCN Red List.
The exact number of these fish is unknown, as most of them spend their lives in deep underground waters beneath the cave where researchers cannot reach them, but all indications confirm their extreme rarity.
Fortunately, Bobcat Cave is already protected because it is home to the endangered Alabama cave shrimp, and constant water quality monitoring and biological surveys have been conducted there since 1990, which also helps protect the newly discovered devilfish.
