Female Anthias wasting away no idea!!!!

[Renegade]

give her time relax, and leave her alone there is always gonna be one that doesn't do as well as the others, Keep in mind she could have had previous problems. You should see how they come into the fish stores you'd be amazed at what they live through, with that said sometimes the stability of your tank only prolongs there death by providing an environment in which they can try to recover but in the end do not pull through. good luck with the fish.