The freshwater drum, Aplodinotus grunniens, is a fish endemic to North and Central America. It is the only freshwater species in the genus Aplodinotus. It is also known for its succulent flesh, but many fishermen are put off by its mucus lining and dank smell. Freshwater drum possess an adapted swim bladder which is able to produce sound. Sound production is thought to be related to spawning activity where many drum will gather in pelagic waters of an ecosystem and begin drumming.
It is also called shepherd's pie, silver bass, gray bass, Gasper goo, Gaspergou, gou, grunt, grunter, grinder, and croaker, and is commonly known as sheephead or sheepshead in parts of Canada, the United Kingdom, and the United States.