Originally Posted by Sniperhank
It could be if it ate something too large for it to digest and it is being stressed out.
I very, very seriously doubt that is the answer.
I've seen anemones eat feeder goldfish before with no problems going in or coming out.
as a matter of fact just last week I had a couple of rummy nose tetras that didn't make it and I fed them to the anemones, no issues whatsoever.
remember, they eat fish in the wild, or anything that happens to get caught and is relatively soft bodied.