Pecos Gambusia (Gambusia nobilis)

Picture of Pecos Gambusia (Gambusia nobilis)

TPWD © Dave Schleser. Educational use permitted.

Texas Status
U.S. Status
Endangered, Listed 10/13/1970
Pecos gambusia are about 2 inches in length when fully grown.
Life History
Small invertebrates and algae form the diet of the Pecos gambusia. It is primarily a surface feeder. Pecos gambusia bear live young. Females produce up to 40 young every 4 to 5 days. Their population numbers are believed to be stable at present.
Spring-fed pools and marshes with constant temperature are essential habitat for Pecos gambusia.
Distribution of the Pecos Gambusia (Gambusia
 nobilis)Historically, the Pecos gambusia was restricted to the Pecos River basin in southeastern New Mexico and western Texas. The populations that once existed at Leon Springs and Comanche Springs were lost when these springs went dry during the mid-1950's. Today, the Pecos gambusia is found in Jeff Davis and Pecos counties in west Texas. Presently in Texas, populations of Pecos gambusia occur near Balmorhea in aquatic habitat supported by nearby springs and at the man-made ciénega. A population also occurs in Leon Creek and in Diamond-Y Spring outflow north of Fort Stockton.
As with the other endangered desert spring fishes, the primary threat to the survival of the Pecos Gambusia is the loss of the spring-fed waters that provide their habitat. In many parts of west Texas, more water is being withdrawn from aquifers by pumping than is being replaced by rainfall. Hybridization and competition with introduced species that have similar diet and habitat requirements pose especially serious threats. Predation by Green Sunfish and Largemouth Bass can become a major problem in areas where there is no submerged vegetation or shallow water to provide protection from predators.