Behind the beak, in the throat, sits a second set of jaws. Plates of fused teeth grind every mouthful of coral rock to powder before it goes any further, and what comes out the other end is sand.
A parrotfish this size processes a few hundred kilograms of reef a year and voids it as clean carbonate grains. On many tropical coasts most of the beach was manufactured this way, one bite at a time, by fish. Stand behind a feeding one and you will see it happen: a puff of fine white cloud, several times a minute, drifting down onto the reef.
The mill runs constantly because the food is poor. What the fish is after is algae growing in and on the rock, and to reach it, it eats the rock. The grinding plates wear out and are replaced continuously from behind, a conveyor of new teeth moving forward through the throat.
One warning attaches to this species that does not attach to most of its relatives: it appears in ciguatera records. The toxin comes from dinoflagellates at the bottom of the food chain, accumulates upward, survives cooking, and cannot be detected by looking at the fish. It is a reason to leave it in the water, which is where it is doing something useful anyway.
It is the blunt-headed one, up to forty centimeters, with a pale green patch at the base of the tail in terminal males. Books also print it as the daisy parrotfish; the two names are one fish.
The genus. Chlorurus Swainson 1839 - chloros (green) + oura (tail). ETYFish
The species. Chlorurus sordidus (Forsskål 1775) - dirty. ETYFish
- blunt rounded snout, no forehead hump
- pale green patch at the base of the tail in terminal males
- females and initial-phase fish gray-brown, often with a pale band across the body
- the second common name, daisy parrotfish, belongs to this same species
- up to 40 cm
Why it's threatened
Threat classification from the IUCN Red List.











