Royal Sea Cucumber

Found singly on hard bottoms, close to rubble and sand patches, of lagoons and reef slopes.

One of the largest sea cucumbers, the upper surface is rounded while the lower surface is very flat. The body wall is thick and smooth. The ventral mouth is surrounded by 18 blunt tentacles. The upper surface is covered in rounded tubercles. Warty growths form an unbroken line along the side of the body.

Some sea cucumbers crawl around on the bottom slowly filtering sand through their tentacles to gather food, while others spread their tentacles above them to capture plankton. A number of sea cucumbers feed nocturnally while others feed by day.
There are sea cucumbers that hardly move while others are more active often perching on tall sponges to feed.
Sea cucumbers often attract hitch-hikers like shrimps and crabs that crawl over their skin, also pearlfish that enter via their anus.
As a means of defence sea cucumbers can expel their intestines or respiratory organs in the form of sticky threads, but these can quickly regenerate.
Juveniles often mimic sea slugs.
Some types of sea cucumbers are edible and considered a delicacy in the Far East countries.