Nice Betta.
Mine is like that too and he has become aggressive, He killed 2 tank mates this morning, I had a few Platy's in with him. I had to put 3D backgrounds into the tank because he was obsessed with his reflection in the back of the tank.
this poor guy has no idea what to think right now. He swims his heart out until he gets tired and lays down on a small patch of wood, just out of sight of the camera. Next thing you know he is at it again, exploring and diving between the plants, swimming through the driftwood until he can't go any longer and has to take a break. I hope he is going to like it!