That's an awesome looking tank! Are the dividers clear where they can see each other?
Both my classroom bettas, Twinkle and Rocket, passed away months before the end of the school year, but Twinkle was so aggressive that if he ever even caught a GLIMPSE of Rocket when I would carry his tank to clean it, he would get extremely frustrated and chew all his fins off... poor little guy. I always had to use that drop solution (forgot what it's called, Bettamax?) in his water to help regrow his fins. I always did my best to make sure he could never see Rocket, keeping them on separate shelves, but those few times he'd see him during transport - fins gone in a matter of days.