Chiefly in the names of animals, especially fish: having a red belly or red underparts.

The redbreast sunfish, Lepomis auritus.

Any of several North American minnows of the genus Phoxinus, which have red undersides, black and yellow stripes along the sides, and yellow fins; especially P. erythrogaster. Also with distinguishing word.

Any of several dark-coloured American turtles of the genus Pseudemys (family Emydidae), typically having reddish coloration on at least the margins of the plastron; especially P. rubriventris of the eastern United States.