Originally Posted by gemsbok
I wasn't aware that betta fish are capable of damaging themselves to that extent overnight. Perhaps you're right. Why would he only bite himself when I'm not looking, though? Is there anything I can do to prevent it, besides staring at him for the rest of his life? :P
He wouldn't bite when you're around because he can pay attention to you. Of course you couldn't stare at him forever :D. But you can have lots of decorations in his tank to explore. You can also put interesting things outside of his tank to look at, and you can change those around to keep them around. A lot of people have had good luck with that. You don't have to buy anything special, but you could put pictures next to his tank, flowers, toys, etc, and change them around now and then. My fish loves to look at the things outside, and loves it when I put something new there, she'll stare at it for hours, from as many different angles as she can.