I've had a yellow clown goby for about a week, and my fish keep picking on it. The main culprits are my six line wrasse, lawnmower blenny, and mainly my true clown. Every time the goby tries to leave his corner, which he sits in all day, the clown rushes at him and puts him back in his place. Are they always going to do this? The goby doesn't eat because he's always sitting in a tiny corner under a rock. What should I do?