hi im am new to this and one of the lessons I've learn is never have a small arowana with an open over reason is becuz he will jusp as far as one feet or more high and die. What I did after I got another aro was put a egg crate on top of tank and seal it with plastic wrap and also cut little holes in the wrap and is actually working well for me so never leave an uncover tank with an arowanna he will jump out and die so that is one mistake Ive learn with big regrets