You guys have all touched on great points. This hobby is selfish and anyone who says differently is blind. That doesn't mean people should stop keeping fish
I think there are just as many good points to the hobby as bad...maybe more even.
Fish are very good at adapting and they're survival instincts are amazing at times. We have to remember that as much as we like to give our fish human emotion or traits (anthropomorphism) they just do not have them. He may be looking out the window and bored in your mind but its not the same as a person being bored. He is most likely just thinking of food
Well I would imagine he is still quite stressed from all the moves lately but that will pass.
The longer I have kept fish, the more I make decisions right for the FISH and not myself. Thats why I have now moved towards smaller more suitable fish for aquariums. I have actually been amazed by what I have been missing too! Wow there are so many incredible little fish out there. I am not saying I think no one should keep tangs or big fish, I certainly think its fine in the right sized tank but more people need to have the thought process you have about this tang. He does need a home but if the store is able to sell large tangs for $300 very fast, they will keep doing it. If that $300 tang sits there for a long time, as sad as that is for him, it may save other large ones as the store may not be as quick to bring in large tangs that don't sell...in theory. We all know it doesn't work that way or we would never see these tangs in stores.
I really do wish people would stop buying them and stores would make them a special order for people with 300G + tanks. Thats human nature of ryou though...we need the biggest ones we can possibly get...North American nature anyways.