Topsail Chub

Kyphosus cinerascens, commonly known as the topsail sea chub, is a species of marine ray-finned fish in the family Kyphosidae. This species is characterized by 11 dorsal fins and 12 anal fins and is widely distributed throughout the Indo-Pacific region. As a herbivore, its diet strictly comprises phaeophytes, chlorophytes, and rhodophytes.

Adults can grow up to 45 cm in length and exhibit colorations ranging from blue-grey to brown or black. These fish have a pale body marked by dark lines separating the rows of scales. Kyphosus cinerascens inhabits the Indo-central Pacific and Atlantic Oceans, including regions near the Greater Caribbean and parts of 🇧🇷 Brazil. They are typically found in areas with algal-covered hard substrates, such as exposed, surf-swept outer reef flats, lagoons, and seaward reefs, occupying depths of 24–45 m. Their habitats are predominantly located within equatorial, tropical, and subtropical climate zones.

These fish are diurnal, commonly observed swimming in schools of ten or more during the day, feeding on algae-covered rocks and free-floating algae particles. At night, they tend to be solitary, though their nocturnal behaviors remain largely unexplored.

In Hawai'i, there are five known species of Kyphosus, four belonging to the Kyphosus genus and one to Sectator ocyurus. Due to their role in controlling algal populations, the State of Hawai'i has recommended protective measures for these species.