Thank you for your reply. I agree with you. The first fish it consumed was near death from a power head mishap. This incident was an unfortunate surprise for me. I'm remembering that right before the incident with the Naso, he was lingering dangerously close to and above the nem. I've made a couple of serious mistakes setting up this tank and this is one of them. I intend to keep the nem but perhaps not in this tank.

My first thought when I read this earlier was the naso was ill. I have always kept large carpet anemones as well as bubble tips. Have had perching fish like mandarins, hawk fish and many little wrasses. Only time I have had a fish go missing was a ill or injured fish. As we speak I have 40 ish fish in my tank with 2 large carpets each over 15 inches I have seen the fish swim into them chasing food no issue.

Can you post a few pics of your tank? I'm interested in the nem placement as well as water flow/power head placement.