Hi, my black ghost knife fish is approx 5 years old, and has always lived in a community tank. In the last 4 months or so, he/she has started being very active at the top of the tank, even swimming vertically with about 1/5th of his body out. He/she has even made contact with the glass lids. Nothing has changed recently, still doing weekly 1/4 tank water changes, temp is steady at 25c, and ph sits close to neutral. Feeding twice a day with frozen blood worms, sinking pellets or flake. I'm only going to take a guess, but maybe he has suddenly noticed his reflection ? Maybe becoming sexually mature or territorial ? There's a pic attached, hopefully it works. thanks !