I'm not sure who said anything about a sailfin, that was a different thread.
I read that article from Coral Magazine and it sounded like a whole lot of justification for keeping tangs in small tanks - based on the fact that it isn't convenient for the average marine aquarist to accommodate a tang. Everyone should be able to own a Dory, right? If you don't have the space or cash for a large enough tank, don't get a tang! It's that simple, I'm not sure why people don't get it. You don't see many people trying to keep a horse on their front lawn, do you? I'm not trying to criticize anyone, but I really do believe that people think a surviving fish is a "happy" fish. I agree with his point that when comparing to the ocean, a 4' tank vs a 6' tank is really a silly argument. It doesn't change the fact that I wouldn't place a tang in anything less than a 6' tank. A 6'x6' cube would be even better! I also own a parrotfish, and I believe he is even MORE demanding than several of my tangs. I am not under the impression that tangs are the only fish in the aquarium trade that have these magical tank size requirements. Be conscientious when choosing your fish and pick fish that will thrive in your tank.