Blue Parrotfish

The Blue Parrotfish (Scarus coeruleus) is a large western-Atlantic parrotfish that is unusual for being uniformly blue at all life stages, lacking the strong colour-phase differences of most parrotfish. Big adults develop a pronounced bulge on the forehead, giving the head a squared, snout-like profile. Like other parrotfish it grazes algae from reef rock with a fused beak, contributing to reef health and sand production. It is one of the larger Caribbean parrotfish and a conspicuous, evenly coloured presence over the reef.

The Blue Parrotfish is identified by:

• Uniform blue coloration over the entire body and fins.
• A parrot-like beak of fused teeth.
• In large males, a bulging forehead and blunt snout.
• Large size, commonly to ~75-90 cm.

Being solidly blue with no strong stripes or contrasting phases separates it from other Atlantic parrotfish.

Blue Parrotfish live on coral reefs, seagrass beds, and sandy reef margins from about 3 to 25 m in the western Atlantic, from Maryland and Bermuda through the Gulf and Caribbean. They favour reef areas with plenty of algal-covered hard substrate for grazing, and larger individuals range widely over the reef.

Blue Parrotfish graze algae from reef rock and dead coral by day, scraping with their beaks and grinding substrate, which produces sand. They often forage singly or in small groups and may follow larger grazers. At night they shelter in reef crevices. Like most parrotfish they are protogynous hermaphrodites, with dominant males spawning with females, though this species retains its blue colour across phases.