July 1, 2026, 3:30 am | Read time: 2 minutes
It’s the sugar-white beaches that many people equate with a vacation in paradise and that simultaneously symbolize pure relaxation. But why are the dream beaches in tropical regions so much whiter compared to many beaches in Europe? The reason has something to do with fish excrement.
Parrotfish come in the most dazzling colors, sometimes blue, sometimes yellow, sometimes violet–with spots, dots, and stripes. They live in tropical regions, such as the sea off the coast of Australia, the Maldives, and Hawaii. And it is precisely these colorful marine creatures that are the reason why the sand on the beaches there is so brilliantly white; more specifically, their droppings are to blame.
The fish nibble small algae from the coral reefs with their beak-shaped mouths, ingesting limestone particles and other calcareous components, as the nonprofit organization Waitt Institute based in Washington writes in a publication. Because parrotfish cannot digest the calcium from corals, they simply excrete the tiny white particles. The Waitt Institute calls this process “pooping sand.”
Also interesting: 70 percent of Caribbean beaches were formed by parrotfish excretions
Up to 320 Kilograms of Sand per Year
They spend 90 percent of their day nibbling on algae. The amount of white sand they produce during digestion is still astonishing: A single parrotfish, which can reach a length of 12 to 47 inches, can produce up to 320 (!) kilograms of sand per year. This sand is washed ashore and accumulates there.
Also interesting: Why you should definitely pee in the sea
With so much excrement, it is not surprising that according to Dr. Sebastian Ferse, a coral reef ecologist at the Leibniz Center for Tropical Marine Research, who is quoted in a video by “The Weather Channel,” more than 80 percent of white tropical beaches consist of fish excrement.
Parrotfish Save Corals
In addition to sand production, parrotfish do something good with their diet: They save corals. Because too many algae can literally suffocate and destroy corals, parrotfish free the coral reefs from the plants with their nibbling. So, for this reason alone, you shouldn’t eat the fish.