An exquisitely patterned fish, the giant yet gentle Napoleon wrasse is a favourite fish to encounter for divers in many regions of the world. This is because, in areas where they are still not wary of humans, they seem to actively seek out tactile interaction, and have even been known to form bonds with individual scuba divers whom the wrasse recognise and seek out.
Most often they will approach divers, using their constantly roving eyes to follow and scrutinise their movements. Look into its eyes and you can not help but be struck by this fish’s obvious intelligence and awareness. They seem to enjoy being stroked and will lean against the pressure of your hand. Sometimes it will even give a diver a gentle nudge or a brush, just like a dog acts when it wants to be petted.
The Napoleonfish can instantly be recognized by its size, colour and shape. It is one of the largest reef fishes in the world and is the largest member of the wrasse family. They can grow up to 230 cm and weigh 190 kg. They have fleshy lips and a hump over the head that is similar to a Napoleon hat. The hump becomes more prominent with age.
Colours vary with age and sex. Males range from a bright electric blue to green, a or purplish-blue. Mature males develop a black stripe along the sides, blue spots on their body scales, and blue scribbles on the head. Juveniles can be identified by their pale greenish colour and 2 black lines running behind the eye. Females, both old and young, are red-orange on the upper parts of their bodies and red-orange to white below.Maori wrasse, like all other wrasses, have protrusible mouths, with separate jaw teeth that jut outward.
Humphead wrasse spends most of their time feeding during the day. Adults are usually solitary, spending the day roaming the reef and returning to particular caves or ledges to rest at night. In some areas, they are very inquisitive, but in others where they are hunted, they are very shy. In the Red sea, it is a very curious fish, where the fish have been fed with boiled eggs. Nowadays it is forbidden to feed Napoleon wrasse with eggs due to the high level of cholesterol that was found in dead specimens in the area.
Napoleon fish are carnivorous and eat during the day. They can be seen feasting on shellfish, other fish, sea stars, sea urchins and crabs, crushing the shells to get at the animal within. They also crush large chunks of dead coral rubble with peg-like teeth to feed on the burrowing mussels and worms.Napoleon wrasse are one of the few predators of toxic animals such as sea hares, boxfish and crown-of-thorns starfish, and are therefore an important part of the marine food chain in maintaining a balanced and healthy coral reef.
Pairs spawn together as part of a larger mating group that may consist of over 100 individuals. The planktonic eggs are released into the water, and once the larvae have hatched they will settle out on the substrate. Adult females are able to change sex but the triggers for this development are not yet known.
Napoleon wrasses are extremely long-lived, known to survive for at least 30 years, and take around 5 to 7 years to reach sexual maturity, meaning they are extremely slow to increase populations.
This species is found throughout the Indo-Pacific oceans, from the Red Sea and the coast of east Africa to the central Pacific, south from Japan to New Caledonia. It is very rare in South East Asia thanks to the Asian restaurant trade and illegal fishing, but is very common in the Red Sea and the Maldives due to park ranger control.
The Napoleon wrasse is mainly found on coral reef edges and drop-offs. Juveniles can be found among branching corals in shallow lagoons, while adults prefer the upper margins of clear lagoon pinnacles and steep coral reef slopes to a depth of at least 100 metres, but occasionally up to 160 metres deep.
They move into shallow bays during the day to feed and tend to move into deeper waters as they grow older and larger. Adults, therefore, are more common offshore than inshore.
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This piece was prepared online by Panuruji Kenta, Publisher, SEVENSEAS Media