Desert fishes are some of the most endangered in the United States. Many species exist for which the critical habitat needs are poorly known. The Zuni Bluehead Sucker Catostomus discobolus yarrowi is one example, an imperiled fish recently listed as endangered under the U.S. Endangered Species Act of 1973. Based on the proposed listing rule the majority of Zuni Bluehead Sucker populations are located in streams on the Navajo Nation in Arizona. Additionally, new genetic information raises the possibility that Bluehead Suckers Catostomus discobolus on the Navajo Nation may be a distinct genetic unit closely related to the Zuni Bluehead Sucker. We examined adult selection of microhabitat conditions (i.e., water velocity, substrate size, over-head cover, water depth, instream cover and mesohabitat conditions (i.e., pool, run riffle), and compared environmental characteristics of occupied sites were compared to those of all available sites to identify habitat that was suitable and preferred for each target species compared where fish were present to what was available in the stream in both high and low flow conditions. We used electrofishing, seining, and snorkeling to evaluate fish occupancy in six streams containing our target species. Zuni Bluehead Suckers and Navajo Nation Genetic Subunit Bluehead Suckers occupied similar environmental characteristic ranges; low velocity pools, over sand, silt, and pebble substrate, at water temperatures ranging from 2-21°C, and a wide range of instream and overhead cover. Suggestions for managing habitat for the target species include constructing livestock exclusion fences around sections of stream to reduce bank erosion, managers should maintain and construct more instream cover, include promoting overhead cover (e.g. maintaining large trees bordering streams), and more pools. A thesis on this work was completed January 2016 and results are now being prepared for publication. Partners include the USFWS and the Navajo Nation.