What fish poops out white sand?

What eats coral, poops sand and wraps itself in a ball of mucus? The parrotfish, of course! These colorful reef dwellers in fact play a significant role in maintaining populations of coral and algae within the reef they call home. If these fish didn’t eat the algae that they enjoy, coral would not be able receive the proper amount of sunlight they need in order to survive and would be smothered. Different species of coral have a special relationship with zooxanthellae; a type of algae that utilizes photosynthesis to make food. The coral, in turn, provide carbon dioxide and other elements that are essential for photosynthesis.

Since these fish prefer the algal covering found on coral for dinner, they end up munching on the coral itself. Teeth that are shaped like long, thin plates plus a sharp, beak-like mouth allow parrotfish to consume different coral species. After they tear off a chunk, flattened teeth in the back of their throats grinds the coral pieces down into a fine, sandy substance. No stomach is present in the digestive systems of parrotfish. Rather, the coral sand hops on the intestine express, makes a one-way trip out the fish’s rear-end coming to a complete stop on the ocean floor. Due to their strange preference in food, parrotfish eliminate hundreds of tons of coral reef sand throughout their lifetime!