The scalefin anthias lives in dense shoals above coral reefs, along drop-offs, outer slopes and channels well exposed to the current. It feeds on zooplankton, which it catches in open water, never straying far from the reef, where it takes refuge at the slightest sign of danger. Within these shoals, a territorial male dominates a group of females and juveniles.
Males and females are easy to tell apart: the orange females are smaller, while the males sport a purplish livery, a purple spot on their pectoral fins and an elongated dorsal ray.
The scalefin anthias is a protogynous hermaphrodite, meaning that it is born female and can turn into a male during its lifetime. Shoals are organised into harems, within which a territorial male dominates several females. When he disappears, the dominant female changes sex to take his place.
Spawning takes place at dusk, with the male mating with several females in succession. The eggs, released into open water, drift with the currents before the larvae settle on the reef.
Did you know?
In the scalefin anthias, sex change is driven by social life. When the male of a harem disappears, the dominant female turns into a male in just a few weeks, whereas this process can take several months in a group with no male.
