Originally Posted by bluebettafish
I'm trying to understand my betta's behaviors. When I came home tonight, he was swimming like he's mentally ill. Staying on the side of the tank where the current is stronger (by the water filter and water coming out of it) and swimming up and down and occasionally bouncing off the wall and the ground. Is he just playing or...what??
I noticed similar behavior in FredFish when I moved him to the mostly bare 5g to do a full water change and fresh meds in his betta bowl hotel. My take is that both yours and mine somehow see "reflection-fish". Fred does not flare at reflection-fish but he does swim patterns on that side of the tank, continuously.
I finally put up two different brightly colored papers on the back and side where I saw he was swimming these nutty patterns, to make reflection-fish disappear. These little guys have an amazing memory. He still went back to the back of the tank, looking for reflection-fish.
If you see yours doing this continually, as FredFish was, I would find a way to keep him away from that side for a few hours per day. My concern was that FredFish would exhaust himself and retard the healing of his fin-rot.
Keep us posted, so we can add to the fish-keeping encyclopedia ;)