I was cleaning out my fish when it wriggled out of my hands as i was transferring ot from bowl to bowl. It landed on the kitchen floor with an almighty smack and lay still. i thought it must be dead, but I put it back in the bowl, and it started to swim, and here we are, eighteen months on, still going strong.
I think fish can stun themselves when they hit a floor or hard surface, but they seem to recover, as yours appears to have done.
All yo can do is keep an eye on him, and either get a bigger bowl, or lower the water level in the one you have to prevent his kamikaze actions in the future.