Maintaining the refugia populations has been largely ineffective, blamed on the small founder population size of each refugia as well as maintenance failures. The Point of Rocks refuge population unexpectedly had individuals appear with pelvic fins, which are not found in the species. Genetic evidence showed that around three individuals of the closely related "C. nevadensis", which do have pelvic fins, invaded Point of Rocks between 1997 and 2005, hybridizing with the Devils Hole pupfish. The "C. nevadensis" genes quickly became highly prevalent in the gene pool, with researchers concluding, "...we add hybridization to the long list of problems that have conspired against successful propagation of "C. diabolis" in artificial settings outside of its native habitat". The School Springs population was extirpated in 2003, the Hoover Dam refugia population became extirpated once more in 2006, and the Point of Rocks refuge was extirpated in 2007.