Five species of fish have been found at Rattlesnake Springs. Two of these species are native—roundnose minnow and greenthroat darter. The other three species are non-native fish and they include green sunfish, largemouth bass, and western mosquitofish. In the summer of 2007, a project was completed to remove the non-native green sunfish and largemouth bass from the pond. These fish were relocated to an appropriate location on the Pecos River, where they are native. The western mosquitofish have only been found in the natural channel and these fish are removed when found.