The pale, eyeless fish flickered in the net, and Jonathan Armbruster knew immediately that something was different. For most of his career, when Armbruster — a cavefish expert at Auburn University — spotted something unusual, it turned out to be the same species wearing a slightly different look. Not this time.
"I've seen plenty of things that looked different before," Armbruster said. "They all turned out to be exactly the same. But when I looked at these, I thought, 'No, these are different.'"
The fish pulled from Bobcat Cave in Huntsville, Alabama in February 2025 turned out to be not just a new species but an entirely new genus — the first such discovery in decades of searching. Scientists have surveyed this cave, located on Redstone Arsenal, for roughly 40 years. The new creature has been named Demogorgonichthys arcanus, the demon cavefish.
The name came from Pamela Hart at the University of Alabama, who had been keeping a list of mythological beings in case she ever named a cave species. Armbruster suggested Demogorgon, a figure familiar from the TV show "Stranger Things" — though its roots stretch back to John Milton's "Paradise Lost." The second part, "arcanus," simply means hidden or secret.
What makes this discovery remarkable is that scientists did not simply give a new name to an organism they already knew existed. "Most of the time when we discover new species, we are finding differences within organisms we already knew were there," Armbruster said. "This was different. This was a new discovery that had not been seen before, and that is really rare."
The new fish lacks the coloration found in its cousin, the southern cavefish, and has a distinct snout shape and body form. Genetic analysis revealed that part of its rhodopsin gene — connected to light sensitivity — is missing. "With this fish, we don't see that," Armbruster said. "Part of the rhodopsin gene is missing, so it is no longer functional."
Researchers have spotted no more than about 20 of the fish at one time, and the creature may spend much of its life deeper in the aquifer, beyond human reach. "It may have been living down in the aquifer and only recently made its way up," Armbruster said. "Or it may have been there before, and we just never saw it."
The cave's location on Redstone Arsenal, a federal military installation, may have helped protect the species. Even as Huntsville has grown around it, large areas of the landscape have remained undeveloped. Cave species, however, need more than just the cave itself protected. "When we think about conserving a species like this, it is not enough to protect the cave," Armbruster said. "We have to protect the land around it, because that land is the recharge basin for the cave and the aquifer."
The discovery, published in the journal Scientific Reports, adds a new chapter to Alabama's remarkable cave biodiversity, where life has adapted in astonishing ways to life in perpetual darkness.