The big Mediterranean grouper with a massive mouth is the dusky grouper (Epinephelus marginatus) or merou brun. They can live up to 50 years, change colour to camouflage themselves and can grow up to nearly 5ft in length—making large males a favourite target of spear fishers (they are all male...another grouper trick is to change sex once it reaches a certain size) but there are many stories of how they can be friendly around divers and become local celebrities (until of course some out of towner comes and nabs them). They are one of the only animals that eat invasive and poisonous lionfish.
Most of the ones sold on fish stands are smaller, 1-3kg females. The fillets are simply baked in the oven, but there are dozens of other recipes, too.
Image by albert kok