Groupers are fish of any of a number of genera in the subfamily Epinephelus of the family Serranidae, in the order Perciformes.The word “grouper” comes from the word for the fish, most widely believed to be from the Portuguese name, garoupa. Groupers are teleosts, typically having a stout body and a large mouth. They are not built for long-distance, fast swimming. Their mouths and gills form a powerful sucking system that sucks their prey in from a distance. They also use their mouths to dig into sand to form their shelters under big rocks, jetting it out through their gills. Their gill muscles are so powerful, it is nearly impossible to pull them out of a cave if they feel attacked and extend those muscles to lock themselves in.