How do I stop my Betta from fighting its Reflection?

Did you just introduce your fish to the bowl? If so this could be normal behavior my male betta took a good week to stop flaring at himself in the gl. And he still does it every now and again. It's not bad for them to flare. Though he shouldn't be doing it all day and night. If he goes at it for maybe an hour or so without stop or if he's doing every ten to fifteen minutes then he's still giving himself some time to rest. I wouldn't worry too much. If it persists or this is a behavior that he's had since he's been home (more then a week-week and a half) then I would look up a way to block the reflection. Perhaps change the lighting or something.