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A Rare Fish Found Underground in Death Valley Is Making a Comeback
The endangered Devils Hole pupfish, which lives in an underground cavern in California’s Death Valley, has increased in number after conservation efforts. Its recovery matters because the tiny fish is exceptionally vulnerable to changes in its isolated habitat.
Groundwater pumping has lowered water levels in the cavern, while earthquake waves can dislodge algae the fish eat. After earthquakes in 2024 and 2025 left fewer than 40 fish, conservationists introduced captive-raised pupfish and supplied extra food. Divers counted 77 in a spring survey and 137 in the latest count last month; researchers remain uncertain how the fish first reached Devils Hole.
In short
- Devils Hole pupfish numbers rose to 137.
- Earthquakes and groundwater pumping threaten their habitat.
- Captive breeding and extra food have supported recovery.
Explained simply
The Devils Hole pupfish is a small, endangered fish found only in a water-filled cavern in Death Valley, California. Its entire wild population lives in this isolated habitat, where it feeds on algae growing on a submerged rock shelf.
The fish is vulnerable to changes in its surroundings. Pumping groundwater can lower the cavern’s water level, and earthquake waves can disturb the algae it depends on. Conservationists monitor the population and have raised pupfish in captivity to support it when numbers fall.
Researchers do not know how the fish first came to live in Devils Hole. Its recovery is being watched because a change in this single habitat can affect the whole wild population.