The Pecos gambusia (Gambusia nobilis) is a species of fish in the Poeciliidae family endemic to the Pecos River in Texas and New Mexico in the United States. This two-inch species, as most of its family, is a livebearer. Females produce broods of up to 40 fry every four to five days. The fish are omnivorous, eating algae and small invertebrates, and are endangered due to loss of their spring-fed desert habitat.