The Parrot fish family (Scaridae) has approx 95 species of fish, apart from their amazing colors and beauty they are also quite interesting fish. they mostly bite on coral and have a parrots beak like mouth which is how they get their name. This particular Parrot fish in the video below is about 3 feet long. They are mostly considered as herbivores but may not necessarily be vegetarian.
Something very interesting about these Parrot fish are that they make a cocoon from their mucus. Its like a balloon or a sleeping bag they create generally at night for them to sleep inside. This cocoon may be for the purpose of protecting them selves by hiding their scent from predators. It could also be kind of like a mosquito net to keep the parasites off their body. Maybe even like a warning system from potential predators like moray eels, when the cocoon bursts the fish would flee.
For those of you interested in Night Diving, this is some thing to look for, mostly these parrot fish would be in their bubble or cocoon at night.