The Cottidae are a family of fish in the superfamily Cottoidea, the sculpins. It is the largest sculpin family, with about 275 species in 70 genera. They are referred to simply as cottids to avoid confusion with sculpins of other families. Cottids are distributed worldwide, especially in boreal and colder temperate climates. The center of diversity is the northern Pacific Ocean. Species occupy many types of aquatic habitats, including marine and fresh waters, and deep and shallow zones. A large number occur in near-shore marine habitat types, such as kelp forests and shallow reefs. They can be found in estuaries and in bodies of fresh water.