Heavybeak Parrotfish

Chlorurus gibbus, commonly known as the heavybeak undefined, gibbus undefined, or 🌊 Red Sea steephead undefined, is a species of marine ray-finned fish from the family Scaridae. It is primarily found in the 🌊 Red Sea.

Chlorurus gibbus is a large undefined species that can reach a total length of 70 centimeters (28 in) and weigh up to 2.2 kilograms (4.9 lb). Juveniles are characterized by longitudinal black and white stripes, while adults display a vibrant blue coloration with a green and purple sheen in males and a yellow sheen in females.

Endemic to the 🌊 Red Sea and the Gulf of Aqaba, Chlorurus gibbus has not been observed in the 🌊 Gulf of Aden where its closely related species, Chlorurus strongylocephalus, can be found. There is a report of Chlorurus gibbus presence in Socotra (🇾🇪 Yemen), which still needs to be verified.

Chlorurus gibbus inhabits shallow reefs and adjacent sandy areas in lagoons and bays, typically at depths ranging from 2 to 30 meters (6.6–98.4 ft). Adult individuals tend to form schools over outer reefs with abundant algae growth, feeding primarily on filamentous algae. These undefined have a recorded lifespan of up to 14 years. They are protogynous hermaphrodites, organized in harems consisting of a single dominant male. Despite this social structure, they coexist harmoniously with other species without territorial behaviors. Parrotfish possess powerful fused teeth that form a beak, enabling them to graze on filamentous algae growing on dead coral. This feeding behavior often takes place amidst sediment clouds. The species is oviparous, with males and females forming pairs for spawning. At night, they create a protective bag made of mucus and bubbles to ward off nocturnal predators.

Chlorurus gibbus was originally described as Scarus gibbus in 1829 by the German naturalist and explorer, Eduard Rüppell (1794-1884), with the type locality identified as Al Muwaylih, Tabuk Province in 🇸🇦 Saudi Arabia. Swainson later established the genus Chlorurus in 1839, designating Scarus gibbus as its type species. Chlorurus gibbus, together with Chlorurus strongylocephalus in the 🌊 Indian Ocean and Chlorurus microrhinos in the west-central Pacific, form a species complex.

Chlorurus gibbus is commercially fished in the central 🌊 Red Sea and constitutes a significant portion of the undefined catch at the Jeddah fish market.