i sometimes roll up a paper ball or something and throw it by the tank they go after it like a cat chasing a ball lol my peacock bass were the best for this they would go crazy lolPossible. Could be something as simple as light coming through the window and hitting a certain way. My fish, which I've noticed with most of them, go after any fast movements or shiny things whether it be light, a finger, another fish etc. there was a video on YouTube if a guy using one of those red lasers, and having his aimara chase it all around the back of the tank, he also seemed to have high flow in the tank, but the aimara powered throughout like what looked to be effortlessly.