Introduction
Devil’s Hole is one of the worst nightmares for a fish, as it has extremely hypoxic conditions and critically high temperatures. That means, nearly anything that goes into it would die. These beautiful pupfish are always on the edge, with such a low population in such a limited area. This fish is found nowhere else on Earth.
Fewer than 40 Devils Hole Pupfish remain in the wild, making them arguably the rarest fish species on the planet. The question that still puzzles scientists is: how did this species come to inhabit such an extreme environment? And what makes their survival so important?
People often ask, “Should this fish even exist in such an extreme environment?”
And honestly, I find myself wondering the same — how and why?
Is the pupfish truly a miracle?
— Kevin Wilson, Ph.D., Supervisory Biologist, Death Valley National Park
Hidden within Death Valley National Park, Devils Hole was carved out thousands of years ago by a powerful geological fault, and that’s what opened it up. Kevin Wilson describes it as a “window into the aquifer” — a rare glimpse into the hidden groundwater beneath Death Valley.
The true depth of Devils Hole remains largely a mystery. Divers have explored the cavern, and the maximum measured depth is 436 feet, yet its irregular walls and narrow passages suggest it could go even deeper. The warm, oxygen-poor water makes exploration extremely challenging, adding to the sense of mystery surrounding this isolated habitat. This unfathomable depth highlights just how extreme and unique the environment is for the Devils Hole Pupfish.
Devils Hole’s water remains a constant 93°F, with scarce oxygen and only a trickle of sunlight reaching the feeding shelf, creating a harsh environment for the tiny pupfish. And also, that limits the amount of algae that grows.
The pupfish originally got its name because it acts like a puppy; they likes chasing each other.
How long have the pupfish lived in Devils Hole?
Scientists estimate that the pupfish have inhabited Devils Hole for thousands of years.
Counting the pupfish started in 1972, with scientists relying on a combination of scuba dives and surface observations to estimate the population size. Historically the highest count was just 540 fish.
— Kevin Wilson, Ph.D., Supervisory Biologist, Death Valley National Park
In 1966, the Endangered Species Preservation Act Came into effect, and the first species on that list, Devil’s Hole, is one of the group of fish in 1967.
The Devil’s Hole Pupfish is kind of an odd conundrum because they can live in extremely tough conditions, and at the same time, they are extremely delicate fish. UNLV found that when the dissolved oxygen goes low, they start producing ethanol, and essentially, the time gets tough, the fish gets a little bit drunk, and it helps to survive the complete lack of oxygen. These are extremophiles and they are living at the edges for what a fish can survive.
Olin Feurbacher
Fish Biologist and Manager
Ash Meadows Fish Conservation Facility
Despite their small size, these fish carry immense symbolic weight. They are a reminder that even in the harshest environments, life can find a way. They challenge our understanding of ecological limits and inspire a deep respect for the tenacity of living organisms. The Devil’s Hole Pupfish exists as both a biological marvel and a cautionary tale—a species that survives only because humans recognize the importance of protection and stewardship.
In the quiet, sun-dappled waters of Devil’s Hole, the pupfish continue their delicate dance of survival. Their world may be small, isolated, and extreme, but it is a world that holds extraordinary lessons about resilience, adaptation, and the fragile beauty of life on the edge.
To explore the fascinating story of these incredible fish further and see stunning footage from the field, visit the original YouTube inspiration here: YouTube Documentary on Devil’s Hole Pupfish.
