It makes a grunting sound by grinding its pharyngeal teeth, amplified by its swim bladder, and forms large stationary schools by day that scatter at night to feed.
What defines this group — Reef fish
The bony fish that live against coral and rock: the living backdrop of almost every dive.
A bony skeleton, scales, and a rigid gill cover closing over the gills.
A swim bladder acts as a float: they hold their depth without swimming.
Many change colour, pattern — sometimes even sex — over the course of their life.