You can find an amazing and colorful Parrotfish on your diving in Koh Tao at many dive sites.

The parrotfish family contains ten genera and about 90 species. It was named «parrotfishes» because the shape of their teeth resembles a bird’s beak plus the fact they swim with their pectoral fins in a bird-like fashion. They are often brightly colored.
The teeth of the parrotfish are uniquely designed to scrape algae from coral and rocks. This is its main food source. It is also able to grind up pieces of coral and excrete the indigestible sand. One parrot fish can chew coral into 90 kg of sand each year. Their teeth keep on growing continuously. Some species of parrotfish secrete a mucous envelope to sleep in during the night. This mucous is thought to give it some protection from predators. Some male parrot fish maintain harems of females. If the dominant male dies, one of the females will change gender and color and become the dominant male. The parrotfish plays an important role in the health of the coral reef — it feeds on algae that could smother the coral if left to grow.