I would not be worried about a fish that did not want to eat dry processed food.
Yesterday I didn't have time to feed my animals so they fasted. Occasional fasting is healthy in several ways, including expelling waste from the body and allowing the tanks biofiltration to "catch up".
Assuming a fish is picking at food growing in the tank, why not feed the tank the things that make natural foods grow better/faster? Feeding planktonic foods like algae paste and pulverized frozen foods makes all kinds of bugs, tiny polyps and algae grow which in turn feeds the larger animals. Just a thought.

Aloha

P.S. One of the two anemones has healed nicely and can go home. The other is healing more slowly and needs to stay a little longer.