The yellowmouth grouper feeds on fish (1) (2) (3) (4) (6), and juveniles show an intriguing behaviour in order to approach otherwise wary prey. Known as ‘aggressive mimics’, the colouration of the juveniles mimics that of the clown wrasse, Halichoeres maculipinna, a species that is harmless to the yellowmouth grouper’s prey. The deception is further enhanced by folding down the fins, adding to the wrasse imitation (1) (7).
Like many groupers, the yellowmouth grouper has an unusual life history, known as protogynous hermaphroditism. All yellowmouth groupers start life as females, reaching maturity at around 40 to 45 centimetres in length, at an age of 2 to 4 years. However, between the ages of around 5 to 14 years old (at a length of 50 to 64 centimetres), individuals change sex and become male (6). Yellowmouth groupers may spawn at any time of year, although peaks have been recorded between April and May in the Gulf of Mexico (6). Juveniles grow rapidly during the first two years of life, after which growth slows significantly. The lifespan of this species may be long, reportedly up to 41 years (6) (8).