Fish problems

I have a 30 breeder I am really trying to find the perfect fish I really like the yellow tang but the tanks to small. Right now I have 2 clowns 1 diamond back goby 1 peppermint shrimp and a Midas blenny I am
Looking for something to be the king of the tank and swims around a lot. What would be some good options I am willing to trade out the goby to make more room.