Red-eared slider

The red-eared slider (Trachemys scripta elegans) is a semiaquatic turtle belonging to the family Emydidae. It is a subspecies of pond slider. It is the most popular pet turtle in the United States and also popular in the rest of the world. It is native only to the southern United States, but has become established in other places because of pet releases and has become an invasive species in many introduced areas, like California, where it outcompetes the native western pond turtle.

http://en.wikipedia.org/wiki/Red-eared_slider