i like small fish. i used to watch one of my brother's baby fish swim around his 55g tank. he was the only fry that survived and he would get all the time in the world to explore every crack and crevice that was available to him. it made me think that in my next life (assuming there is one) i'd want to be a fish, (or a dolphin cuz theyre always so happy), because there's so much underwater that you could explore as opposed to being a bird and flying through a vast sky of.. well, nothing.
small fish just makes you think that there's so much out there in the world. big fish don't really give you that perspective, esp. if theyre kept in small tanks where they get to swim about 5 feet, turn around, and swim the 5 feet again. with a small fish, the 5 ft would seem like miles.