The reef stonefish is considered the most venomous fish in the world, but its most effective weapon is its camouflage: perfectly still, it blends in seamlessly with rocks on the seafloor. Its venomous dorsal spines are used purely for defense, never for hunting.
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.