The hump is a sexual dimorphic trait - the hallmark hump is not found in female fish. Image Source Fact #2: Only the male humphead wrasses have a hump

The females have red, orange and white scales. The males typically display blue hues, ranging from dull blue to blue-green to electric blue. The males and the females differ in color. The fish displays a remarkable ‘diamond’ pattern on its body, in hues of yellow and sometimes even purple. The scales of this colorful fish are predominantly blue and green. In fact, it is one of the largest fish - males can be up to two meters long and can weigh as much as 180 kg. The humphead wrasse is an incredibly large fish. The fish is famous for its protruding bump on the forehead, peculiar broad lips, strong teeth, and unique ‘eyelashes’ (black lines behind the eyes). Fact #1: Humphead wrasse has a remarkable appearance During spawning, they may come in groups of hundreds. Occasionally, divers come across a pair of a male and female fish. On an average, no more than 10 humphead wrasses can be found in a 100 m × 100 m area. In open waters, they usually travel alone. The adult fish are seen at the outer coral edges. The young ones usually stay in shallow waters and sea grass beds. At night, they hide in reef caves and other shelters, such as coral crevices and ledges. Humphead wrasses can be found up to a depth of 100 m. In daytime, divers find them roaming around the outer reef slopes. The humphead wrasses are diurnal animals, active during the day. It also covers the waters from South Japan to New Caledonia. This area spreads from the Red Sea and the East African coast to the central Pacific. Its natural habitat are the Indo-Pacific Oceans. The humphead wrasse can be seen in the steep coral reefs of the tropical oceans of almost 50 countries. Popular names: Napoleon fish, Napoleon wrasse, Maori wrasse, Blue-tooth groper