Help Me Please

[digital_fish]

Shyte!

My yellow tang as far as I ever thought is quite small. About 2 inches long. The blue tang was about the same size and did grow a slight bit over the year. And like I said, the blue tang never did seem to have a problem in that small 15 gallon tank. I also have 2 clowns and 2 B/W damsels. 5 fish in total. One cleaner shrimp, and 5 snails.

Also when I first started the hobby, the guy at the fish store said I should only keep the damsels for a short while because they will get aggressive. They did seem a little aggressive at first but they all seem to get along now. I tried to give them back to the store but they wouldn't take them. I kept them because I didn't want to kill them. Should I really get rid of them still and if so what could I replace them with? Should I just keep my yellow tang and hope for the best?