The Reef’s Most Important Vegetarian

By Gretchen Wichman

Rainbow Parrotfish (Image: Ned DeLoach).

The most lovely of all Osteichthyes! Parrotfish are the fluorescent friends of Bonaire’s coral reefs; they use their strong jaw and fused teeth (beak) to chomp on coral and algae. In turn creating a healthy reef, keeping the algae at bay, and creating homes for anemone, coral, and jellyfish polyps. Every time a Parrotfish bites off a chunk of substrate it is audible, hence earning the name parrotfish due to their noisiness as well as their beaming hues.

Males possess a radiant rainbow of scales, while half a dozen young females follow closely behind in a drab coloring of brown, tan, gray: this is known as a harem. When the supermale is caught by a fisherman or eaten by an eerie eel the most dominant female rises in power to lead the harem. Hormones are released which stimulate the female’s organs to undergo a transformation of appearance and function, such that in a matter of weeks the female has become bedazzled with new scales. All parrotfish are hermaphrodites and revamp their coloration as they grow, regardless of changing gender.

As the sun trickles down the sky, disappearing behind the curvature of the horizon, the parrotfish retreats to depths beyond the swallow reef. These diurnal creatures embrace nightfall by secreting a thick layer of mucus from an organ in their head, securing a cocoon around their compressed body. Gnathiid isopods, blood-sucking crustaceans, love to snack on unprotected Parrotfish while they are in deep sleep, yet when their prey is surrounded by mucus it is no longer appealing. The moray eel cannot even smell its dinner, the parrotfish, through the thick cocoon. It is to mankind’s benefit these nomadic herbivores protect themselves well through the night because at the light of dawn they are protecting our earth, giving hope to the coral reef ecosystem, a chance for survival.

 

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