Townsend's Anthias

Found in harems, sometimes mixed with other Anthias, over mud and rocky bottoms of deepwater reefs.
Western Indian Ocean - Persian Gulf

Anthias are often found in large schools, often in their hundreds or thousands, feeding high above the reef on zooplankton.
They start their life off as females, and when there is an opening for a male, will change to head up their harem of females.
Males are much more colourful, and often have filamentous streamers which they use for their mating dance, and to deter other males.