Gambusia speciosa, the Tex-Mex gambusia, is a species of fish in the family Poeciliidae which is found in the United States and Mexico.

[3] In Mexico its range covers the states of Chihuahua, Coahuila, Nuevo León and Tamaulipas while in the United States it is found in New Mexico and Texas.

[1] In Texas it is restricted to the Devils River and its tributaries in Val Verde County.

[4] The habitat of the Tex-Mex gambusia includes springs, outflow channels, marshes and the margins of small to medium-sized streams.

[2] This species was described by Charles Frédéric Girard in 1859 with the type locality given as the Río San Diego, near Cadereita in Nuevo León.