fairy wrasse, midas blenny, firefish, yellow coris wrasse (if you dont mind him eating your cleanup crew) yellow assessor (if you can find one) sunburst anthias, royal gramma, yellow clown goby are all beautiful fish that stay small. maroon clownfish are aggressive though, esp. as they get bigger so I would be wary of him attacking a newcomer. rearrange your rock before a new addition to break up the territory if possible.
and if you decide to go the green chromis route, I KNOW that you wont regret it. they are the most intense beatiful irridescent greenish blue color. dont count them out. not many green fish to choose from in general and they really do fit the bill for a small peaceful reef safe colorful fish.
