Panama Porkfish

Found during the day, close to shelter in stationary schools, dispersing at night, hunting for food, over shallow, hard bottoms, of coastal reefs.
Eastern Pacific - Mexico to Peru

In some areas of the world 'Grunts' are better known as 'Sweetlips' distinguished from other species by their very large rubbery lips.
'Grunts'because they "grunt," the grunting sound is produced by their flat teeth plates rubbing together and this is amplified by their air bladders.
Found either singly or in schools hovering or motionless over the reef during the day, becoming nocturnal predators.