The yellow-bellied water snake lives throughout deep east Texas and eastward throughout much of Louisiana, Arkansas, Mississippi, and Alabama. It is an aquatic species generally found near the larger and more permanent bodies of water, such as marshes, swamps, river bottoms, and along the edges of lakes and ponds. They feed mainly on fish, frogs, and tadpoles. Adults typically reach 30 to 48 inches in length. The record is 59 inches.
Due to its plain dark greenish to black dorsal color, stout body, aquatic nature, and nasty disposition, this harmless species is often mistaken for the venomous western cottonmouth.