The Bi-colour/Bicolor Anthias, also called Yellow-back Basslet (not the same as the Goldback Anthias), is in the Bass and Grouper family.
It is native to reefs of the Indian Ocean and western Pacific.
They have a yellow top and a pink underside. They grow to 14cm long.
Most are female. If the breeding male dies or is removed, a female will transition to become male.