Help with Next Fish

Just wanted to see if anyone had any good ideas what i should add for my next fish, right now, in my 55 gallon tank i have 2 O clowns, Yellow Tang (yes i know the tank is to small) and a neon goby, now i won't be buying a new fish for 3 weeks or more, but what would be a good next choice, i was thinking maybe 2 or 3 Blue/Green Chromis or a royal gamma basslet, anyone have any other ideas what would be a good fish to add to my tank with all the other ones i have so far?



thanks!