Devil's Hole Pupfish

Devils Hole is reported to have the most extreme conditions: a nearly constant temperature of 34°C, no direct sunlight during the winter which limits primary production, and nutrient availability and dissolved oxygen levels near lethal limits for most fishes (2-3 ppm). It is restricted to the upper 30 m of this 3.5 x 22 m water-filled cavern (Ref. 127857).

Occurs in deep limestone pools. The entire population feeds and breeds in an area 20 meters square, a limestone ledge along one side of Devils Hole. Not a seasonal killifish. Is very difficult to maintain in aquarium.