Cleaning up the reef

These colourful parrotfish swimming off the coast of the Philippines are just one of more than 80 species of parrotfish which live in the world's tropical seas. The Indo-Pacific region boasts the most variety and these particular thick-bodied fish have large scales and a beak of fused teeth which they use to scrape algae off reefs and rocks. Some also eat coral, which they grind up with plate-like teeth in their throats. Researchers say parrotfish play a critical role in the health of coral reef by eating algae that can impede coral growth. They also help replenish the white sandy beaches near these tropical reefs. How? After parrotfish digest the edible parts of coral, they excrete what's left as sand - a lot of sand. In some species, a single parrotfish can poop almost 1000lb (453kg) of pearly white sand each year. But perhaps some trivia is best not dwelt upon.
© Tim Fitzharris/Minden Pictures