Hello I have a black lined flying-fox who loves to swim, circle and jump. The problem is he has a small tank (28L). When he was smaller he loved to do back-flips out of the water, now he still jumps but hits the aquarium lid, and then smashes into the gravel. He has been doing this for about a week (the hitting the top and bottom of the tank, otherwise he is just an energetic fish).
Question: I am wondering if he is going to be stressed in the small sized tank and if he would prefer being in a bigger tank, I'm kinda guessing that is the reason, but just thought I would ask some knowledgeable fishy people...
and I'd love to get a bigger tank but there is no room for one... and I am quite proud of this fish... so would have to sell him if his odd behaviour is due to a cramped environment.