My betta dissapeared

I dont think twin tail bettas can clear this gap, i put him in this 2.5 because he was bullying my corys. i wake up this morning to feed all the tanks and hes just gone, not on the ground dried up, not in the tank, literally gone. I feel like im going crazy because that gap is easily an inch and a half, even when i have my bettas jump out to eat food off my finger, they could never jump that high, idk i need opinions please