If it was dead for too long, it may be spoiled and can cause demise of your anemone.
I used to have a CBB. I feed it steamer clams. Every other day I would put a froxen steamer clam intot the tank in the morning. In the afternoo, it there is any meat in the clam, I would just scoop it out and feed it to my Magnifica. It was doing very well until I started to do this. It deflates and get into that vicious cycle and died on me. The only thing I can come up with was the lelfover clam, after 6-8 hrs in thetank, was not a good thing to feed my Magnifica. Spoiled.