Three snorkelers swimming over sand. Is sand fish poop?
Are we swimming in fish poop? Photo Ishan / Unsplash

We’ve all heard the rumors, but is it all true? Do we really lay down our beach towels on tiny pellets of poop? Let’s check out this burning question and answer, once and for all, is sand really fish poop?

Is Sand Fish Poop?

Yes! Some sand is fish poop. More specifically, the fish will be parrotfish. A species of fish that bites, scrapes, and grinds bits of algae off rocks and dead corals using their strong parrot-like beaks. They digest the inedible calcium-carbonate reef material (which is usually coral skeletons) in their guts, and then excrete and poop it out as sand!

Is ALL Sand Fish Poop?

No, not all sand is fish poop. Sand is made of various bits of natural material and from many different locations. Most of the sand material starts off in-land, from rocks.

These large rocks break down from weathering and eroding over thousands and even millions of years, creating smaller rocks.

These smaller rocks then wash down rivers and streams, breaking into even smaller pieces.

The bits of rock will make it to the ocean and be tossed and turned from wind, waves, and tides, eroding into tiny pieces that finally become sand!

How is Sand Formed on Beaches?

Sand is formed on beaches by the constant movements from the wind and water. The coloring of the sand, however, comes from the material.

The tan color of most sand beaches is from iron oxide. The rocks which were originally quartz will color into a light brown from iron oxidization.

That amazing black sand comes from volcanic material eroded over time, from lava, basalt rocks, and other dark-colored rocks and minerals, and is typically found on beaches near volcanic activity such as in Amed, Bali.

You will also get sand from the by-product of living things such as shells. Some coral reefs are inhabited by foraminifera; unique aquatic organisms that live in red shells, and when they die their shells are washed ashore. The red color from these shells mixes with the sand giving the beach a pink shade when exposed to the sun.

Read More: Why Do Seahorses Hold onto Coral and More Amazing Facts about Seahorses! and Are Sharks Attracted to Bright Colors?

So there you have it, the next time you lay on that sunny tropical beach, just think about the billions of tiny grains of sand under you, and how some of it may have come through a parrotfish!