My 3yr+ old betta has been in a 2gal tank for most his life because that's the way I have always had bettas in the past. But Ive learned a lot and do think they deserve better. Anyway, I thought he was sick awhile back and decided not to move him to my relatively new 15gal (tall) for fear of spreading disease. It has been months and he is actually doing great, I am unsure if it was just an injury or what but today I moved him to his big retirement home with a few other fish and a nerite. Hes been so sweet and just exploring. He hasnt shown any interest in any of the fish, just the pond snails. Ill keep an eye and make sure my mean female molly doesn't mess with him.