Parrotfish have strong teeth that form a parrotlike beak, which they use to scrape algae off hard coral. Some species don’t mind eating bits of coral as well, and they later poop out a fine sand that washes up on land to form beautiful white beaches.

Clownfish and sea anemones live together and help each other. The clownfish help the anemones by cleaning their tentacles and luring other fish for the anemone to eat. The anemones, in turn, allow the clownfish to hide among their poisonous tentacles without stinging them.

Cleaner wrasses are small fish that keep bigger fish clean by feeding on their parasites and dead skin. The bigger fish recognise the wrasses by their colours and the dance-like way they move.