I have a 55gal tank w 25 lbs live rock, live sand, percula clown, bar goby, prawn goby, green serpent starfish, and a chocolate chip star fish. The Prawn Goby (most recently added) eats the substrate then spits it back out, and i did see it nipping at some algea on the gorgonian, but here is the problem, the gorgonian keeps being tipped over and my plate coral frag keeps getting mashed against the rock no matter where i put it on the sand. and i always see the cc starfish on top of the gorgonian and my button polyps. is the star fish eating them or just moving across them. and i never see it happen but im assuming the prawn goby is moving the coral because that never happened before...any ideas? also is a yellow watchman goby reef safe becasue i saw it eat 3 feeder guppies almost the size of my clown!!!would it be safe because the clown always stays at the top? wow thats a lot of stuff to ask!!!