The bluehead wrasse or blue-headed wrasse (Thalassoma bifasciatum) is a species of saltwater fish in the wrasse family (Labridae) of order Perciformes native to the coral reefs of the tropical waters of the western Atlantic Ocean. Individuals are small (less than 110 mm standard length) and rarely live longer than two years. They form large schools over the reef and are important cleaner fish in the reefs they inhabit.