colors are all a breeding thing. the only visible difference between tank raised and wild caught is..... none. as stated above no clown needs an anemone to survive, in fact tank raised are actually less likly to host in an anemone. my tank raised clown wont go near my anemone but hosts instead on a powerhead, or feather duster.
I agree with ponie in saying your LFS isn't too bright. thats definatly one of the dumber things I have heard when describing a tank raised clown. they are heartier, used to tank life, great eaters, and their colors are as good if not better than wild caught, due to good breeding programs. if his are poorly colored and dumb it sounds like his breeder is inbreeding the heck out of his clowns, and overall showing that idiots should not be allowed to breed (or breed anything)