Health is important. Stress weakens all livestock. Wild collected or tank raised a fish will still be stressed when put inside a plastic bag again and placed once again in a new home. Simply looking at a fish (even if you eyeball it for a week or 2) in a store and bringing it home will not insure that it does not have something harmful that can be passed on to other livestock. QT is important with anything added to your display. Sure some people have better luck than others at this Russian Roulette but why risk it for a few $$ quarantine setup?
