Parrotfish off the coast of Negros Oriental province, Philippines

© Tim Fitzharris/Minden Picture

Colorful cows of the reef

These brightly colored parrotfish are swimming off the coast of Negros Oriental province in the Philippines. There are dozens of species of parrotfish and they live in abundant numbers in the world's tropical seas. These thick-bodied fish have large scales and a beak of fused teeth they use to diligently scrape delicious algae from 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 reefs by eating algae that can choke off 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 1,000 pounds of pearly white sand each year. But never mind that—some trivia is best not to dwell on.