Any one know what these are? They are really small so it was hard to get a decent picture. They are on a fairly new tank (it's been up for about 6 months) and the tank currently holds a clown fish pair that are going to be moved to a much larger tank in a week or two. This tank was started with ocean direct live sand and dry Marco rock. The only other thing that was added to the tank was 2 neurite snails that both died with in a week of being put in the tank. That was about 3 months ago.
The creatures seem to have a shell like structure and have a fan like thing sticking out to filter feed.
If they are problematic I really don't want to transfer them to the larger display tank.