By behaving this way, the chameleon fish can assume the colour and size of about 50 other species of fish in the surrounding seas, all of them much larger and more imposing than the Chameleon Fish.

The fish can maintain this disguise for up to eight hours, before they have to revert to their normal size. If a chameleon fish is caught by fishermen, it will change colour every two minutes, something which alarms the people of the area, who invariably believe the fish is the devil’s work and will throw it back into the sea.

Excerpt from – Animals Evolution Avoided