I agree watching fish in a aquarium is very therapeutic. I get the same results watching Opo graze in the backyard.I have a filter system that came with the tank. I bought a TopFin and wondering whether or not to buy the same size or a 10 gallon. They say you don't need it for a betta but that doesn't make sense to me because rain would do the same for a mud puddle. I just make sure the flow doesn't blow him around in the water. The size I buy will depend on it's dimensions and the size of tray I can find. Just to make the tank movable if necessary. It sits on my entertainment stand and it's better then tv even with 1 little fish.