One of the world’s rarest fish is showing encouraging signs of recovery, with the population of endangered Devils Hole pupfish more than doubling over the past year.
The National Park Service (NPS) counted 137 Devils Hole pupfish during an October 10th population survey, nearly twice the 77 fish recorded during the spring 2026 survey and more than double the 69 observed in fall 2025. The results offer a positive development for a species whose entire wild population lives in a single location within Death Valley National Park.
Devils Hole is a deep, water-filled cavern in Nevada’s Amargosa Valley, where the tiny fish survive in an extremely isolated environment. The pupfish depend heavily on a shallow limestone shelf inside the cavern, which provides important feeding and spawning habitat.
Earthquakes Pose A Major Threat
Despite the population increase, Devils Hole pupfish remain highly vulnerable to environmental disturbances. Earthquakes are a particularly significant threat because the resulting waves inside the cavern can dislodge algae and other food sources from the limestone shelf.
Two earthquakes in 2025 disrupted the habitat and contributed to population declines. Even an earthquake in Panama on October 9, 2026, nearly 3,000 miles away, initially appeared to cause stress among the fish. However, biologists found the population in healthier condition during a subsequent visit.
“It’s exciting to see Devils Hole pupfish numbers increase so significantly over the past year. These results reflect the dedication of our scientists and conservation partners working to protect this extraordinary species.” – Death Valley National Park Superintendent Mike Reynolds.
Conservation Efforts Showing Promise
Several conservation efforts have helped support the population through recent challenges. Between March 2025 and February 2026, scientists released 72 captive-raised pupfish into Devils Hole to help rebuild numbers.
However, researchers believe most of the 137 fish counted during the October survey were born and raised naturally inside the cavern. That’s particularly encouraging considering Devils Hole pupfish have an average lifespan of just 10 to 14 months.
Conservation teams also provided supplemental feeding while algae recovered following the habitat disruptions. Monitoring data from the U.S. Fish and Wildlife Service’s Ash Meadows Fish Conservation Facility helped guide those efforts.
Biologists have monitored the population through scuba diving and surface surveys since 1972. Although the numbers naturally fluctuate, the latest count represents a significant step in the right direction. Continued monitoring, research, and habitat management will remain critical to ensuring this remarkably rare fish survives for generations to come.