High Quality Content by WIKIPEDIA articles! The freshwater drum, Aplodinotus grunniens, is a fish endemic to North and Central America. It is the only species in the genus Aplodinotus. The freshwater drum is a member of the family Sciaenidae, and is the only member of the group that inhabits freshwater for its entire life. Its generic name, Aplodinotus, comes from Greek meaning "single back", and the specific epithet, grunniens, comes from a Latin word meaning "grunting". It is given to it because of the grunting noise that mature males make. This noise comes from a special set of muscles within the body cavity that vibrate against the swim bladder. The purpose of the grunting is unknown, but due to it being present in only mature males, it is assumed to be linked to spawning.