Groupers, also known as gropers, are fish from the subfamily Epinephelinae of the rather large family Serranidae. They typically have a stout body and large mouth and are not built for long-distance or fast swimming. They can be quite large, lengths over a meter and weighing up to 100 kilos are not uncommon, however, species vary considerably. They swallow prey rather than biting pieces off it. Without many teeth on the edges of their jaws, they use heavy crushing tooth plates inside the pharynx.
Their diet consists of fish, octopuses and crustaceans. Some groupers prefer to ambush their prey, while others are active predators. 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 in order 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. Many groupers are important food fish, and some of them are now farmed. Unlike most other fish species which are chilled or frozen, groupers are usually sold live in markets. Some species of grouper are small enough to be kept in aquariums, though even the small species tend to grow rapidly.