Stream temperature, flow, and the presence of non-native fishes can affect the distribution of native cold- and cool-water fishes. This is especially true for native fishes that have already experienced significant contractions in their historic range. The Gila and Mimbres drainages, located in southwestern New Mexico, support a unique cold- and cool-water native fish fauna adapted to the arid stream systems in which they evolved. These fishes, however, are losing ground to non-native fishes and to loss of habitat due to intermittency from stream drying. We implemented a temperature monitoring network throughout current and historical fish distributions to assess localized temperature effects on the distribution of the native fishes. We are working with the National Forest, U.S. Fish and Wildlife Service, New Mexico Department of Game and Fish, and citizen scientists to provide a comprehensive understanding of the dynamics that air and water temperature have on these arid-land fishes for future water planning needs.