This long-lived fish has a fascinating and complex life-history. It is a protogynous hermaphrodite, meaning that individuals first function sexually as females and then later, at least some of the mature females change to males. It is thought that this sex change can occur at a wide range of sizes and ages, although not all individuals change sex. A brown-marbled grouper can live for over 40 years, an incredibly long time for a fish, and can reproduce for over 30 of those years, during which time they form large aggregations to spawn (2).
The brown-marbled grouper is one of the largest fish predators on coral reefs (5), and is mainly active at dusk, when it feeds on fishes, crabs and cephalopods (3) (6). This secretive and wary fish may be ciguatoxic (5); that is, the flesh may be contaminated with a toxin that can make humans very sick if consumed.