I have one of my bettas in a 5 gallon bow front aquarium and recently I noticed his tail fin has split into two. I see no sign of fin/tail rot. There's no fungus and he looks healthy. Hasn't lost any color and he eats well. He still has his purky personality too. Is it possible he just ripped his fin somehow? He was the first betta I bought and I'm really attached to him. Any help or insight will be much appreciated.