I've had peppermint shrimps who ate aiptasia, but when not fed, also were caught eating coral on a few occasions. I had seen my peppermint a few times eating the head of a candycane coral. I did end up catching him and getting rid of him, but the aiptasia never returned, so I was happy. This was all in a 24g nanocube with a light bioload and a bunch of corals.