How long has the yellow coris been in the tank?I know yellow coris are supposed to be reef safe but I dont trust any with the clams except the fairy wrasse family. One yellow coris can be fine in a tank and another may not. ive learned that fish have different personalities even though they are the exact same species. I know other people who keep blue hippos with their clams just fine but mine takes chunks out of mantles quickly.It took me a while to catch my radiant nipping my clams but once he did they were afraid to expand their mantles fully. Just a thought.