A scientist slipped into a pool beneath a U.S. military base and discovered a fish later named the “Devil’s Cave Fish” after the demon king from Stranger Things
A clumsy fall into an underground swimming pool beneath an active US military base led to the discovery of a strange eyeless fish named after the TV show’s monster.In February 2025, Matthew Niemiller, an associate professor of biological sciences at the University of Alabama in Huntsville, slipped and fell while performing routine environmental monitoring. The accident occurred inside Bobcat Cave, a restricted cave system on the west side of the Redstone Arsenal military base in northern Alabama.“I slipped and fell into the pool,” Niemiller said. “I scared a cave fish from under a shelf because of my clumsiness.”The frightened creature turned out to be a completely unknown genus and species of cave fish. Scientists named it Demogorgonichthys arcanus because it spent millions of years evolving in complete darkness under a busy military installation. Its common name is the “demon cave fish,” inspired by the underground monster from the Netflix science fiction series “Stranger Things.”
An unexpected discovery in the dark
The discovery, described in a new study published in the journal Scientific Reports, surprised researchers because bobcat caves are not an unexplored place. For decades, scientists have regularly visited the cave to study and monitor the Alabama cave shrimp, a federally endangered species.During a visit in February 2025, Niemiller and his research team, including his wife K. Denise Kendall Niemiller and several college students, were working in an area of ​​the cave known as the “shrimp chamber.” After falling into the pool, Niemiller quickly took photos and videos of the fish he disturbed, but he didn’t scrutinize the footage until a week later.
The devil cave fish has a completely different lineage than another cave fish found in the same small cave (Photo: Matthew Niemiller)
When he finally looked at the images, he noticed that the fish did not match the southern cavefish known to live in the same waters. This unknown fish has a different head shape and unusual fin structure.Intrigued by the discovery, Niemiller returned to the cave and collected some specimens. He collaborated with other scientists, including Pamela Hart and Michael Sandel, to study the fish’s physical characteristics and genetics. The results confirmed that the fish is not only a new species, but also a completely new genus of organisms in the family Amnichopsidae.
Naming the beast from an “upside-down” perspective
The idea to name the fish after the fictional monster came from co-author Pamela Hart. The researchers wanted to avoid using place names, which they considered less interesting.The name Demogorgonichthys combines “Demogorgon” (the hellish creature from Greek mythology and modern-day Stranger Things villain) and “ichthys” (the Greek word for fish). The second part of its scientific name, arcanus, means “hidden” or “secret,” reflecting how this creature remained unknown for so long.“I’m an ’80s kid from Indiana, so Stranger Things resonated,” Niemiller told Axios. “It’s a perfect fit.”The appearance of the devil cavefish shows how it has adapted to extreme environments. This fish lives permanently in darkness, has no eyes, and no body color. It comes in a translucent white or pale electric blue color with some pinkish tint caused by visible blood vessels under the skin.
Two apex predators in the same pool
This discovery raises new questions for scientists. Subterranean environments often have limited food, often supporting only one apex predator. However, the devil cavefish shares its small cave system with the southern cavefish.It’s really strange that “two apex predators” would exist side by side in a cave, Niemiller said, having evolved independently for 10 million to 13 million years.Both species are blind, adapted to life in caves and hunting smaller creatures in the dark. However, the relationship between them is not close. Their coexistence suggests that different groups of fish entered the groundwater system at different times and adapted individually to life without sunlight.
safe haven on military land
Bobcat Cave consists of a network of narrow, water-filled tunnels connected by muddy passages. The water level inside the cave can change dramatically, rising or falling by almost four meters after heavy rain. During periods of drought, water disappears into the “shrimp house’s” insulated pools, forcing fish to congregate in small areas.The cave is located within part of the Redstone Arsenal, which has historically been used to dispose of conventional and chemical weapons. Environmental monitoring over the past two decades has found small amounts of metals, including lead, chromium and cadmium, in the cave’s water.Despite these contamination issues in the past, the military base inadvertently protected the land above the cave from growth in nearby Huntsville. If the area is developed for homes or businesses, construction and paved surfaces may alter groundwater movement and disrupt fragile underground ecosystems.The devil’s cavefish is currently only known to exist in this single cave system, but researchers believe it may live in other inaccessible parts of the deeper groundwater network. For now, the discovery shows that unique wildlife can still survive in unexpected places, hidden right beneath major human infrastructure.
