A betta is fine in a 1gal. tank. I had one in there for years and he was just fine. In fact, I had him in a 10 gal and all he did was try to fight so I moved him to the one gal. and he was fine. The puddle thing is because rice patties are not full of water year round. They do dry up. My betta tank was never filtered and had the water changed only as necessary. Point being, a 1gal. is fine for a betta no question about it.