I have a 30 gal cube,reef tank.presently I have a pair of ocellaris clowns a nd a pseudo chromis.I am thinking about getting one more fish and have considered a goby but I have a purple tube anenome at the bottom of my tank and it takes up a lot of the ground space.the clowns live at the top third and the chromes scoots through my rocks most of the time.what would you recommend that would stay small ,be colorful and get along with the rest of my population?