Before anyone bashes me on what I'm about to say, READ EVERYTHING.
So I rearranged the dividers in the 10 gallon and put Bubs back in. This time I kept a VERY close eye on him. The tank lid was propped open and I had my hand over the tank with the net in the other. I was prepared so in case anything happened I could separate them. And then Bubs got out. He managed to wiggle his way through the smallest gap (he took a few scales with him) and got onto Squirt's side.
What shocked me was that instead of him swimming right towards Squirt (he was right in front of him) he fled. He nstantly went to the other corner and hid. Squirt took no notice to him whatsoever. So I kept Bubs in the tank for a good 5 minutes and watched his behavor. And again, any time he was entering Squirt's area, he swam away. At one point they crossed each other's eyes sight (I literally jumped and had the net in the water) but they did nothing. Didn't even flare :/
I removed Bubs after he got himself stuck behind the filter (he found Lucky interesting), and he's back in the 1 gallon until I set up the 5 gallon again.
But to be honest, I'm so confused o.o
The last time they ended up having a flaring contest, but Bubs still stayed away from Squirt. Is it possible that because of Squirt's fins, he looked bigger and maybe more threatening even without flaring?
And just to clarify, no I did not put Bubs back in for the intent of watching him attack Squirt. I put him back in because I adjusted the dividers and I felt no gaps. Obviously, a betta can. I just took pre emptive steps since it did happen yesterday and there was a chance it would happen again.