ONE OF TWO NATIVE TROUT IN ARIZONA. The Gila trout (Oncorhynchus gilae), one of two native trout species in Arizona (the other is Apache trout O. apache – Apache Trout Recovery), is one of the rarest trout species in the United States. Historically, the fish was native to the San Francisco, Verde, Gila, and Agua Fria River drainages in New Mexico and Arizona.