The cypress darter (Etheostoma proeliare) is a species of darter, a small ray-finned fish in the perch family. It is endemic to fresh waters of the central and eastern United States. Its range includes drainages from the Choctawhatchee River, Florida, to the San Jacinto River, Texas, as well as the Mississippi River basin from southern Illinois and eastern Oklahoma to the Gulf of Mexico. It inhabits vegetated margins of swamps and lakes, and backwater habitats during the summer, while in winter it moves to flooded riffles and backwater bayous. It feeds mostly on small crustaceans, as well as insects and their larvae. Spawning takes place during spring and summer, with clusters of up to three eggs being laid, often stuck to the surface of dead leaves. The cypress darter has a very wide rang