Originally Posted by Mister Sparkle
My inclination would probably have been to lower the water level. In less than a foot of depth, I'd bet he would choose an area and "patrol" it.
I can't see the logic in this "guess" at all.
I keep/have kept bettas in 5 gal, 10 gal and 80 gal tanks. They have all appeared to be happy, healthy bettas. The betta in the big tank really seemed to enjoy his space, cruising around the whole tank every so often. That tank was 2 feet deep, and despite some "internet wisdom" that bettas prefer shallower tanks, that is not my experience. He loved it in there !!
Personally, I would not keep any betta-sized fish in anything smaller than a 5 gallon. I know that they can live to a ripe old age in a smaller environment, but that does not mean that the environment gives them optimum happiness. I like to give my fish a little space to exist in, thats all.