College dorm room fish?

I think you could manage a single betta fish. It would be very happy in a 5-10 gallon tank. You wouldn't need to take it home at all on weekends, just feed him before you go. If you save the cup you buy him in it will make taking him home over long vacations easy. If you ever have to be away for more than a few days an can't feed him you can get a slow release food cube that will keep him fed.