Betta Fish: My betta hates Smiskis

i was thinking about putting a smiski in my betta tank (its made of non toxic ATBC-PVC and I've seen some other folks have success with it) but evidently my betta HATES that idea. I've never even seen him flare this much at his own reflection. he's super peaceful and has never attacked shrimp or snails or anything so this was a very funny surprise!