My wife & I have contemplated several different variations under the "what if" we ever owned a LFS scenario. Obviously, cheap is what sells so you must maintain a large section of 'regular' un-QT'd fish. Same as every other LFS. However, I never thought that folks might equate that to mean "sick fish" if you also carried 'premium' QT'd fish. It's a good point and something to think about.
As snorvich will be quick to point out if I don't

, every brick & mortar LFS
must have a maintenance side to carry the business. And being I would have to QT each & every fish for my clients; I don't see why I could not do the same for at least some of my customers. The QT process itself would be done in the back; you don't want customers seeing sick fish or fish they can't buy yet. But whether the QT'd fish would be presented in their own 'premium' section of the store, or it would be more of a, "Psst hey buddy, look what I've got in the back" sorta thing I don't know yet.