Compsopogon caeruleus is a species of red algae that lives in fresh water. It is the only species in the genus Compsopogon and the only representative of the family of compsopogonàcies (Compsopogonaceae). It is found in North America, South America, Europe, Asia, Australasia and Oceania. Compsopogon can tolerate a wide range of conditions in freshwater streams and is propagated by asexual spores.