In the late 1940s, ichthyologist Carl Leavitt Hubbs began campaigning for legal protection for Devils Hole and the pupfish. This led to President Harry S. Truman issuing a proclamation in 1952 that made Devils Hole part of Death Valley National Monument (now National Park). In 1956, the United States Geological Survey (USGS) installed the first water level recorder. The fish was officially listed as an endangered species in 1967, making it one of the first species protected under the Endangered Species Act.