I have a 36g FOWLR has been running for about 3 months. I've had 2 clown fish disappear recently within a week. I also have a Coral Beauty which seems fine. Tested the water and all is normal. Think I might have seen a head of one of the clowns wedged in between the rock and sand but then was gone the next time I went to find it. I also have a white legged hermit crab that is a little on the big side and has killed 4 of his other friends, arco crab, peppermint shrimp and some snails. Could one of the crabs be catching and killing my fish?