Pi is a male ADF that I've had for 8-9 months now, in a 3 gallon Marineland Eclipse tank with a biofilter & heater. He is awesome!!! He loves to eat, sing and entertain us. Within the last couple of weeks I've noticed him banging/ramming his nose into the walls of the tank, mostly at the surface of the water. I cannot find any info online regarding this behavior and was hoping someone here might have some experience or knowledge of it. Other than that he appears fine. His diet consists of Hikari bloodworms, Hikari Tubifex worms, Hikari Mysis Shrimp, and occasionally tuna. Filtration is diffused with aquarium foam so that he isn't thrown around by the current. Water temp is at 77*. Any help would be greatly appreciated. It kills me to see him do this, thinking it's gotta hurt. It's hard enough that I hear it from a few feet away. I'm worried about him. Thanks!