Calotomus carolinus (Valenciennes, 1840)

Maximum Size

Calotomus carolinus (Valenciennes, 1840) reaches approximately 50 centimetres (20 inches) in total length.

Appearance Change Trait

This species changes its appearance dramatically as it matures into adulthood.

Juvenile Coloration

Juvenile individuals are typically mottled orangish-brown with some pink shading.

Terminal Stage Male Appearance

Adult males, referred to as the terminal stage, are blue or green in varying shades, and have pink lines that radiate from their eyes.

Initial Phase Female Appearance

Adult females, called the initial phase, are mottled brown and have slightly bulging eyes.

Jaw and Teeth Structure

The jaws of this species are made up of pebble-like teeth fused together to form a beak that is adapted for eating seaweed; in juveniles, the teeth are not yet fully fused and are visible on the outside of the dental plate.

Geographical Distribution

Calotomus carolinus has a wide distribution across the Indo-Pacific region, ranging from the coast of East Africa (it is not present in the Red Sea, where it is replaced by Calotomus viridescens) through the Indian Ocean to the eastern Pacific Ocean around the Revillagigedo Islands and the Galápagos Islands.

Social Grouping

This species is typically found either alone or in small groups, in shallow reefs or lagoons.

Depth Range

It occurs on subtidal reef flats, in lagoons, and on seaward reefs down to depths of at least 27 metres (89 feet), and can be found deeper.

Habitat Substrates

Within these habitats, it occurs in areas with coral, rubble, seagrass, and algae.

Diet Composition

It feeds on a variety of benthic encrusting algae, the brown algae genus Padina, and seagrasses.

Reproductive Trait

Calotomus carolinus is a protogynous hermaphrodite, and like many other parrotfish species, it undergoes a sex change.

Ecological Role

Along with many of its relatives, it feeds on seaweed and algae that grow on coral, which benefits reef ecosystems because most algae restrict coral growth and prevent corals from maturing fully.