The Atlantic goliath grouper may be solitary or occur in groups of up to 50 or more individuals. Its home range appears limited and the fish produces a booming sound when threatened by divers or large sharks. Variations of these vocalizations also undoubtedly have intraspecific communicative properties (3).
During the breeding season, from July through September, Atlantic goliath groupers gather together at breeding sites in groups of 100 individuals or more, for periodic spawning. The fertilised eggs are scattered in the water column and develop into kite-shaped larvae with long dorsal fin spines and pelvic fin spines (2) (3). About a month or more after hatching, the larvae mature into juveniles of just 2.5 centimetres long and settle preferentially into mangrove habitat (2) (3).
These fish are very long-lived, with a slow growth rate and late sexual maturation. Males begin breeding at four to six years and females mature at six to seven years. However, if the Atlantic goliath grouper is like most other groupers, it may undergo a sex-change part way through life, starting out as a female and becoming male at some later time, although this has never been observed in this species (2).
The Atlantic goliath grouper feeds on crustaceans, such as spiny lobsters, shrimps and crabs, as well as fish including stingrays and parrotfish, in addition to octopuses and young sea turtles. Despite having teeth, the fish engulfs its prey and swallows it whole. Before the Atlantic goliath grouper reaches full size it is susceptible to the attack of barracuda, king mackerel and moray eels, as well as sandbar sharks and hammerhead sharks (2). Once it is fully grown, humans and large sharks are the Atlantic goliath grouper’s only predators (2) (3).