close map

Commonly Asked Questions

Appears in Georgia Aquarium's:
  • Ocean Voyager

Range / Habitat

  • Occurs in the Indo-Pacific from the Red Sea to Algoa Bay, South Africa through the Hawaiian and Pitcairn islands and south to Australia.
  • Found in tropical shallow reefs, caves, wrecks and estuaries commonly to 164 feet (50 m) deep. Full depth range is 13-328 feet (4-100 m).

Physical Characteristics

  • Size
    • Largest of all coral reef-dwelling bony fish.
    • Common length up to 8 feet (2.5 m) and maximum weight of 660 lbs. (300 kg).
    • One of the largest recorded was 9.8 feet (3 m) and weighed more than 882 lbs. (400 kg).
  • Color
    • Juvenile giant grouper are bright yellow with large, irregular black or dark brown bars.
    • As adult, irregular patterns break up and their coloring becomes a muted, mottled olive-gray. 
  • Body Composition
    • Has a very large mouth that expands and protrudes to create a strong suction to draw in prey.
    • Mouth has at least seven rows of teeth on the middle of the lower jaw.
    • The giant grouper’s eyes function effectively in dim light, which gives it an advantage over its prey during dawn and dusk feeding times.
    • Eyes also rotate so grouper can see approaching prey without moving its head.

Diet / Feeding

  • Diet
    • Consists of fish, sharks, juvenile sea turtles and crustaceans, including spiny lobster and mud crabs.
  • Feeding Behaviors
    • Ambush predator that lies in wait while hiding in holes, crevices and reef overhangs.
    • Swallows food whole.
    • Occupies the upper end of the food chain:
    • Few reside in each area; few found on any one reef.

Reproduction / Growth

  • Protogynous hermaphrodite; starts out life as female and can later change gender to become male.
  • Does not reach sexual maturity until it is about 20 years old. Fishing usually removes the largest, and therefore oldest, fish first.

Conservation Status

  • “Vulnerable” on the IUCN Red List.
  • Populations of this species have been drastically reduced worldwide due to overfishing.
  • Population thought to be declining 20 percent rate every ten years.

Additional Information

  • Slow-growing and lives up to or beyond 50 years.
  • Other common names for this species are “Queensland grouper” and “brindle bass."


Encyclopedia of Fishes. 2nd Edition, pgs. 195 -199
Fishes of the Great Barrier Reef. Randall, J. E., pg. 109
Fishes of the Tropical Eastern Pacific. Allen, G. R., pg. 106
Reef Fish. Thresher, R. E., pgs. 153 -155