I have a red lobster along with 2 cleaner shrimp, stars(brittle and sand), feather dusters and other goodies and the ONLY problem I have run across is one morning I woke up and found the plummage from one of my dusters in the claws on the lobster. I honestly don't think the lobster did that though because I have heard that dusters will drop their plummage once in awhile to grow. (they'll grow back). The reason I don't think the lobster did it is because I have other dusters and he has NEVER messed with them.He always stays on "his" rock hanging upside down. I have never seen him go after my shrimps either. Hope this helps?!?