I'll never add clowns to a tank that size again. I just removed a mated pair in my 29 gallon cube. They tore up some frilly mushrooms I had for some reason out of the blue. I mean they destroyed it. So they are gone.
Six lines - nice size, but agressive. Depending on your substrate, if any, may want to pass on this guy.
Possum wrasses, if you can find them, are great. On my list to order but local stores never really carry them for some reason and I don't want to mail order. Forum member here just added one to his 100 and mentioned he rarely sees it. It is shy but he knows it is eating something.
I have a bi-color blenny. Wanted a starry blenny but again couldn't find one. The yellow and green gobies noted above are really nice. I also have a pair of pajama cardinals.