It is listed as threatened by the State of Arizona. The Gila topminnow is found in small streams, springs, and cienegas below 4,500 feet in elevation, primarily in shallow areas with aquatic vegetation or debris. It historically occurred throughout the Gila River system in southern Arizona and at the Frisco Hot Springs on the San Francisco River in New Mexico. It also occurred in most river systems through the State of Sonora, Mexico as far south as the Rio Mayo. Introduced populations exist in small streams and ponds in Santa Cruz, Graham, Gila, Pinal, Pima, Maricopa, Yavapai, and La Paz Counties, Arizona.
Natural populations persist in several Sonoran watersheds.
Gila topminnow prefer shallow, warm, quiet waters associated with spring pools and runs. They can live in a wide variety of water types including springs, cienegas, marshes, permanent and intermittent streams, and along the edges of large rivers. They feed primarily on insect larvae, including mosquito larvae, but also on other small aquatic and terrestrial invertebrates. Topminnows live approximately 2 years. The species is declining due to the introduction and spread of exotic predatory and competitive fishes, water impoundment and diversion, water pollution, groundwater pumping, stream channelization, and habitat modification.