Make sure you have a tight tight tight lid and try not to turn on light or rush the tank. These arowanas are the most spooked I've seen and it makes me cringe every time they freak out. I recently did a water change, touched his tail and he jumped out of the nearly 5' stand, hit the sliding door and flopped on the floor. I was so scared I almost had a heart attack. Luckily he is hardy and only a handful of scales and bleeding occurred. I hope this helps.