The Secret Ingredient to the Perfect Beach Sand? Parrotfish Poop

There’s nothing quite like walking along a tropical white sand beach—the salty wind in your hair, the warmth of the parrotfish poop between your toes.

Yeah, you read that right. Fish poop.

Fish POOP

Like it or not, if you appreciate the white sand beaches of the Caribbean or Hawaii, then you owe your gratitude to one of nature’s many accidental architects—the Parrotfish. Let’s dive in.

Parrotfish, named for their bright coloration and bird-like beaks, are essential players in the world of coral reefs and refer to a group of roughly 90 species found in shallow tropical waters around the world. These remarkable creatures with their fused together, beak-like teeth have a penchant for munching on coral polyps—tiny, soft-bodied organisms that live in colonies that form the foundation of coral reefs. As they graze, they not only consume the algae-covered coral but also inadvertently ingest small bits of coral skeleton. To help things go down easier, parrotfish possess a special set of tooth-like plates near the back of their mouth called a pharyngeal mill which further grind up the jagged bits of coral.

Fortunately for their digestive tract, parrotfish possess a specialized digestive system that breaks down the coral, extracting the nutrients while excreting what remains—a fine, white sand. Imagine millions of parrotfish working tirelessly, day in and day out, contributing to this process. This continuous cycle of feeding and sand production has a profound impact on the underwater landscape.

Now, you might be wondering, how does this add up to the creation of islands? The answer lies in the sheer volume of sand produced by parrotfish. A single large adult parrotfish can produce over 1 ton of sand per year. Over time, this sand accumulates and forms sandy sediments. When combined with other natural forces like ocean currents and wave action, these sediments contribute to the gradual build-up of landmasses, and the birth of islands.

Hopefully, your next visit to a beautiful white sand beach hasn’t been too terribly tainted with thoughts of fish poo between your toes, and you instead have a new found appreciation for our colorful, oceanic, coral-muching friends—the parrotfish.