I just set up my tank and put my two Bettas in. It's a divided 14gal tall. Anyways I haven't been able to put in a permanent divider so I used those dividing suction cup things and some plastic mesh. It bowed in and I had to fill some spaces on the side with extra mesh so they wouldn't get though. Needless to say is looked like a wreck.
I was nervous as hell about it and they one would get through and they would fight when I was gone or something. But nothing happened until I added some fake plants today.
I bought these plants so that they weren't in direct view of each other and stressing out and stuff. I don't cover all the the divider and they can still see each other pretty well but it does provide some cover for them.
Anyways I knocked one of the fill-in mesh pieces loose so there was a hole that they could swim through. Being paranoid I was constantly checking my tank and saw Pepper swim through into Noche's half. I had an "Oh ****" moment and got the net as quick as I could and luckily they were both stunned at seeing each other that I caught Pepper without a problem and put him into a cup. Luckily no one was hurt.
So now the divider is cut in a where where it touches the glass leaving no room for them to even push through it. Still super nervous about going to sleep tonight and waking up to find one of my fish dead and one injured. But I poked and prodded the divider with a ruler and a net and it's holding well. My only problem is is that they can see each other still. I can fit anymore fake plants though.
But yeah, my heart just about stopped for a second there. Now they're just antagonizing each other through the divider.