he will be happier in the 2.5 gallon than the half gallon especially with it having a filter and hood and light. How about heat? Can you maintain a 76-80 degrees that will make him REALLY happy? The plant you mentioned to slow the flow is a good idea too.

You can adjust the filter as high as the betta "likes". If the flow is pushing him a little, but he doesn't "mind" it no harm. If the flow is pushing him a bit too much and he is hanging to a corner or a side of the tank because of it, then turn it down. If the lowest setting is too much, then diffuse it with plants or other decor. I had a betta that liked to swim into the flow of the filter return from time to time, it was kind of a game for him. It would damn near dash him into the side of the tank, but he'd come back for more. His fins didn't get damaged and he is still alive after at least 2 yrs. now. I gave him away before I moved, but as far as I know he is live and doing fine. The reasoning is you don't want to compromise flow for no reason. Flow is important for keeping the tank physically clean as well as biologically "clean". Beneficial bacteria in the filter will be more lively and abundant with the flow. A great addition for a betta tank is live plants and lots of them with some space for free swimming. Good "beginner" live plants that are not too demanding are Water Sprite, Frill/Parrots Feather and Java Ferns. Live plants help 3 fold, appearance, ammonia break down and oxygenators.

thanks everyone. His water is maintaining the right temp. with the small lamp I have stationed on him. He's hiding in the small pot I have for him but I think he'll get used to his surroundings. The snail loves it though!!