The Scorpidinae, commonly known as halfmoons, knifefishes, and sweeps, are a subfamily of the sea chubs, a family of marine fish in the order Perciformes. The Scorpidinae are distributed throughout the Pacific and east Indian Oceans, with species occurring in the waters of North America, South America, Asia, Australia, and numerous islands. Most inhabit the continental shelf in shallow rock and kelp reefs and deeper offshore reefs, whilst others are found well offshore in a pelagic setting.