Let's be totally honest though, the people who care don't buy their fish from petco anyway. Some people you just can't reach, and the type of people who go to petco for advice and saltwater fish aren't the type who would believe you even when toldI was in Petco the other day, and the store help was talking to a woman about the Yellow Tang. Woman goes, we only have a 29 gallon tank, and the store employee goes, this fish will be just fine in there, perfect size tank for this fish. I said, wrong, that fish (mind you I don't have a tang yet) needs at minimum 4' tank, preferably 5 or 6'. I said, sure, at 3" as it is now, it'd be ok in a 29. When it gets to be 6-8" it won't be.
I think she got the Tang anyhows, but I digress.