My Banggai is the first fish I added to the tank, but he's still hiding. He's been there for a week. My other 3 fish hang out with each other in front of the tank regularly. The Chromis keeps following the Clowns, but the Banggai doesn't want to join the gang. Surpringly he is the most aggressive eater. He eats like a pig, but as soon as feeding ends he comes back to his cave. Is this normal?