My tank is new and only had two polyps of zoas that were hitchhikers from the rock I got from a friends tank. After my cycle I added a few snails and a emerald crab. All was well for about 4-5 days and then last night the crab ate the two polyps. Or I would assume its the crab but maybe the snail? They were both very small polyps so no biggie, but Im about to start stocking a few corals, and the first thing in will be a small colony of zoas. Should I evict the crab?