Well I was in Fish Store this past weekend, and probably 20% of their FW tanks had ich, but the fish were still for sale. their marine fish often look starved, distressed, and there was a yellow tank with lesions around its face...again still up for sale.
The owner's the only one who really knows anything. I think he hired some friends, and their girlfriends to help run the place. If there's a girl working when you go there, don't even bother asking them ANY questions...not even "do you carry airline reducers?". That was a 10 minute ordeal until one of the guys came over and had a clue what I was talking about and grabbed them off a shelf under the counter, directly where she had been searching !