I think you would be fine getting a 1 gallon. If you are planning on putting him at a desk that you are at a lot I think that is even better. I have two boys on my desk at the moment and they are very active. I currently have 7 one gallon tanks, 1 2.5 gallon tank, 1 ten gallon sorority, one divided 10 gallon, and 2 five gallon tanks. I really cannot tell the difference in the behavior of my boys in 1's and those in abobve 1's. To say that it is cruel or morally wrong to keep them in a 1 gallon tank to me is not accurate. I am a college student, and only work on the weekends, and nearly every penny I earn goes towards giving my fish better lives(plants, meds, etc.). I have the money to upgrade all of my tanks to larger ones, but if I feel that they are thriving in a one gallon, why would I change their surroundings. I have switched homes for some of them before, and they didn't act the same. I'm not sure where I stand on whether or not I think fish have feelings, so I judge my fish on if I feel they are behaving normally, ie. eating, flaring, swimming/playing/ acknowledging when I come to their tank. The fact that bettas are seen as disposable fish, and as a whole are not known to go to caring owners, I think that the fact that this person took the time to come on here is a good step and may save one fish from dying in a horrible cup. So I will not discourage this person from getting a betta that they would obviously care for, by telling her that it is cruel to keep it in a one gallon because they either don't have the money for a more expensive one or don't have the room, which is my case. The fact that a one gallon can't have a filter or heater is irrelevant to me, as if you care for them properly this won't be a problem. Sorry this post is a little long, I don't normally post on these issues, but felt compelled to do so tonight.