Proteus anguinus is found in the subterranean, freshwater lakes and streams of limestone caves in the Dinaric Alps. The water in these caves is slightly acidic, contains high concentrations of oxygen, and ranges in temperature from 5° to 15° C. Adapted to an aphotic environment, olms usually reside deep within cave systems. They may be found in open streams near the surface during times of high rainfall and flooding. They are generally found over 300 meters below surface.
Range depth: 300 (low) m.
Habitat Regions: temperate ; freshwater
Terrestrial Biomes: mountains
Aquatic Biomes: lakes and ponds; rivers and streams
Other Habitat Features: caves