The dorsal profile of the head and the intraorbital area are convex, The propercle has a rounded corner and a finely serrated margin.

[5] The giant grouper is a species of shallow water fish and can be found at depths of 1 to 100 metres (3.3 to 328.1 ft).

[1] The giant grouper is an opportunistic ambush predator which feeds on a variety of fishes, as well as small sharks, juvenile sea turtles, crustaceans and molluscs which are all swallowed whole.

Fish living in estuarine environments in South Africa were found to be feeding almost exclusively on the crab Scylla serrata.

They are not generally considered dangerous to humans but divers are advised to treat large specimens with caution and not to hand feed them.

Studies in captive populations suggest that the dominant male and female begin the spawning event as nearly the only spawners for the first day or two, but other members of the aggregation fertilize more eggs as the event progresses, with even the most recently turned males fathering offspring.

[8] The giant grouper was first formally described as Holocentras lanceolatus in 1790 by the German medical doctor and naturalist Marcus Elieser Bloch (1723–1799) with the type locality given as the East Indies.

[3] The giant grouper is a highly valued food fish and is taken by both commercial and recreational fisheries.

[1] The first fish to undergo chemotherapy was Bubba, a giant grouper at the Shedd Aquarium in Chicago.