Scientist finds 'demon cavefish' in pool beneath US military base

A scientist stumbled upon a mysterious new species while conducting routine environmental checks at a military base in Alabama. In February 2025, Matthew Niemiller, an associate professor of biological sciences at the University of Alabama in Huntsville, suffered a minor accident while exploring Bobcat Cave, a restricted cave system located on the western side of the Redstone Arsenal military base in northern Alabama. During his slip, Niemiller inadvertently disturbed a previously unknown cavefish, which he later identified as a new genus and species. Scientists named the fish Demogorgonichthys arcanus, commonly referred to as the "demon cavefish," due to its resemblance to the supernatural creature from the Netflix series Stranger Things. Niemiller and his research team, including his wife K. Denise Kendall Niemiller and several university students, had been monitoring the Alabama cave shrimp, a federally endangered species, in an area of the cave known as the "shrimp room." The incident occurred during these routine surveys. Niemiller fell into a pool within the cave and accidentally startled a fish hiding beneath a rock shelf. Initially, he took photographs and videos of the disturbance but did not fully analyze them until a week later. Upon reviewing the footage, he realized the fish did not match the Southern cavefish, a species already documented in the region. The demon cavefish exhibited distinct physical characteristics compared to the Southern cavefish. It possessed a unique head shape and unusual fin structures. Intrigued by this anomaly, Niemiller returned to the cave to collect additional specimens. With the help of fellow researchers Pamela Hart and Michael Sandel, he conducted detailed studies of the fish’s morphology and genetic makeup. These analyses confirmed that the fish represented not just a new species but also a novel genus within the Amblyopsidae family. This finding highlights the potential for undiscovered biodiversity even in areas that have been studied for decades. The decision to name the fish Demogorgonichthys arcanus was influenced by co-author Pamela Hart. She suggested drawing inspiration from pop culture rather than geographic locations, which she felt lacked narrative appeal. The name combines "Demogorgon," a mythical underworld figure and a key antagonist from Stranger Things, with "ichthys," the Greek term for fish. The second part of the scientific name, arcanus, signifies "hidden" or "secret," emphasizing the prolonged obscurity of the species. Niemiller, who grew up in Indiana, expressed personal connection to the show, noting how the name aligns with the fish’s eerie, otherworldly appearance. The discovery has sparked further inquiry among scientists, particularly regarding the ecological dynamics of the cave system. While such subterranean habitats typically support only one dominant predator, the demon cavefish coexists with the Southern cavefish in the same small cave. Both species are blind, adapted to cave life, and feed on smaller organisms. Their independent evolution over 10 to 13 million years raises intriguing questions about resource availability and competition in isolated ecosystems. Researchers continue to investigate how these two apex predators manage to thrive together in such a confined space.