ExpertAggressiveNot Reef Safe

Gag Grouper

Mycteroperca microlepis

Family: Serranidae · Groupers & Basslets

Also known as: Gag, Gray Grouper, Charcoal Belly

Max Size

59"

Min Tank

500 gal

Lifespan

25-30 years

Origin

Western Atlantic, Gulf of Mexico

Diet

Carnivore

Swims

Bottom

About

The Gag Grouper is one of the most commercially and recreationally important grouper species in the Western Atlantic, reaching an impressive maximum size of nearly 5 feet. Its body is typically gray to brownish with darker worm-like markings and blotches that provide effective camouflage against rocky and reef substrates.

In the wild, Gag Groupers are found on hard-bottom areas, rocky reefs, and artificial structures throughout the Western Atlantic and Gulf of Mexico. Juveniles inhabit seagrass beds in estuarine environments before moving offshore to deeper reefs as they mature. They are apex predators that feed on fish, squid, and crustaceans.

Due to its enormous adult size of up to 59 inches, the Gag Grouper is exclusively a public aquarium species. It is completely unsuitable for home aquariums, as even juvenile specimens grow rapidly and require massive water volumes. Only institutional facilities with systems of 500 gallons or more should consider housing this species.

Feeding & Diet

Carnivore

An apex carnivore that feeds on fish, squid, and crustaceans. In institutional settings, feed a varied diet of whole fish, squid, shrimp, and other marine protein sources. Adults should be fed every 2-3 days with appropriately sized whole prey items.

Compatibility

predatorpublic-aquariumlarge-fish-onlyhigh-bioload

The Gag Grouper is an aggressive apex predator that will consume any tankmate it can overpower. In public aquarium settings, house only with other very large species such as sharks, rays, large moray eels, and similarly massive groupers. Completely unsuitable for community setups of any kind.

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Breeding

Not bred in captivity

Gag Groupers are protogynous hermaphrodites that form large spawning aggregations at specific reef sites during winter months. Females transition to males at approximately 10-11 years of age. Captive breeding is not feasible due to the species' massive size and complex aggregation-based spawning behavior.