Gus my silver has a very nasty habit of slamming the glass- only though- at night after i turn the tank light off. He will sit in utter silence for a moment or two and then go bananas. Flopping slamming and doing so in such a way that sometimes I feel like he has jumped clean out of his cage though he never does. Do arowana need a night light as it were? Cause his whatever condition of the dark causes my 80lb dog to berserk as well and she is now more terrified than ever to come in the "scary fish room".