set it up how you like it but also make sure there are few caves and areas for your fish to hide and sleep in...example...my tang has a big cave it fits in comfortably, clowns sleep at ph's, lawnmower blenny sleeps inside a rock hole, chromis sleep in a small cave and my ss goby took all my rubble rock made a cave himself and completely covered it with sand for his little home, also peppermint shrimp sleeps under a rock in the cave