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. They can be quite large, and lengths over 3 feet long and weighs over 200 pounds are not uncommon, though obviously in such a large group species (there are over 13 different species) vary considerably. They swallow prey rather than biting pieces off it. They do not have many teeth on the edges of their jaws, but they have heavy crushing tooth plates inside the pharynx. They tend to eat fish, octopus and crustaceans. They lie in wait, rather than chasing in open water. Their mouth and gills form a powerful sucking system that sucks their prey in from a distance. They also use their mouth to dig into sand to form their shelters under big rocks, jetting it out through their gills. Their gill muscles are so powerful that it is nearly impossible to pull them out of a cave if they feel attacked and extend those muscles to lock themselves in.
The black grouper specifically is a large marine fish, growing up to 60 inches in length and 45 pounds in weight. It has an olive or gray body, with black blotches and brassy spots. Other names include: black rockfish, bonaeci arara, and marbled rockfish. Adults feed mainly on other fish and squid, though the younger fish feed on crustaceans, especially shrimp.
Most fish spawn between May and August. They are protogynous hermaphrodites, which means the young are predominantly female, but transform into males as they grow larger. They grow about a 2.5 pounds per year and generally they are adolescent until they reach about 7 pounds, when they become female. At about 25 pounds they turn to male. Usually, males have a “harem” of three to fifteen females in the broader region. If no male is available, the largest female turns male.