Synanceia verrucosa

Reef stonefish Strategy: background matching, with a dangerous twist. Usually brown or gray, sometimes with patches of yellow, orange or red, it can look exactly like an encrusted rock or a lump of coral as it sits on rubble or coral bottoms, often under rocks or ledges. It is also the most venomous fish in the world, with 13 stout dorsal spines that can inject the venom. That makes it the one animal on this list to look for without touching. It lives across the tropical Indo-Pacific, including much of the Great Barrier Reef. Watch where you put your feet and hands on reef flats, and wear solid shoes when wading.