Personally, and for all of us for that matter, I think 90% of pet fish look the best in large tanks. Way too many pacu, oscars, ID sharks, columbian sharks, etc. are sold to people who cannot adequately house them. I always tell people at PetSamrt or any LFS who big the fish they're looking at is going to get and that it will look its best and be more active in an appropriately sized tank.
It's relatively easy to house a 12" fish properly, all you need is space.
It's relatively easy to house a 12" fish properly, all you need is space.

