My betta went pyschopathinc in my 60 Litre tank 'Convicted for 4 murder's He was.Yeah, I know. XD BUTBUTBUT I've had Bettas who prefer larger spaces. This is not all of them, however, and I'm going to put some more plants in my other 10-gallon because my male Betta seems to enjoy laying on his side under the plants on the sand.
All you need to do is plant it up right, and.... Voila! Happy Betta! Lots of things to explore, and a good, large tank.
Bare in mind the ank did have a few plants in it