Global Range: Native to Africa. First brought to the U.S. in the 1930s and 1940s for laboratory use and later as an aquarium pet. Introduced and established locally in California (San Diego, Orange, Riverside, Los Angeles, Ventura, and Imperial counties) and Arizona (Tucson area) (Stebbins 1985, Lafferty ad Page 1997). Apparently established in Baja California (see Mahrdt et al. 2003). Recorded but not established in Colorado.