The rusty undefined (Scarus ferrugineus) is a marine ray-finned fish species belonging to the family Scaridae. It is commonly found in reefs in the northundefined and the 🌊 Red Sea.
This species is typically found in the 🌊 Red Sea, the 🌊 Gulf of Aden, and the 🌊 Persian Gulf, with populations off the coasts of Bahrain, 🇩🇯 Djibouti, 🇪🇬 Egypt, 🇪🇷 Eritrea, 🇾🇪 Yemen, 🇮🇱 Israel, 🇯🇴 Jordan, Iran, Qatar, 🇦🇪 United Arab Emirates, 🇴🇲 Oman, 🇸🇦 Saudi Arabia, 🇸🇴 Somalia, 🇸🇩 Sudan, and Socotra (🇾🇪 Yemen). It inhabits coral reefs at depths ranging from 1 to 60 meters and is generally abundant.
Measuring up to 41 cm (16 in) in length, Scarus ferrugineus exhibits two distinct color patterns. The terminal phase showcases a multicolored and bright blue-green appearance, while the initial phase, in which these fish are often seen in groups, is characterized by a brownish hue (hence the common name) with light and dark bands and a yellow tail.
These fish are visible in the months spanning from March to November. They are oviparous and protogynous hermaphrodites, meaning they change sex and color as they mature. Three distinct life phases can be observed: juveniles, initial phase adults (typically females), and terminal phase adult males (resulting from sex and color change in females). Adult males in the terminal phase typically form harems. The rusty undefined primarily feeds on benthic algae.
The formal description of the rusty undefined as Scarus ferrugineus was first provided by Peter Forsskål in 1775. Forsskål was a Swedish naturalist, explorer, and orientalist. The type locality, where the species was first discovered, is Dahab on the northwestern coast of the Gulf of Aqaba off the Sinai Peninsula in 🇪🇬 Egypt.
Within its range, the rusty undefined is targeted by artisanal fisheries.
Why it's threatened
Threat classification from the IUCN Red List.
