I would agree...keep it dim for a while. That egg crate can be troublesome in that it gets super bright when the lights reflect off of it. I've had fish in the past really freak out over it. There has been a lot of activity in the tank with him being newly introduced, harassing tankmates, and moving/shifting things around in there. I'd just leave him and the tank be for a while until he completely settles in. JMO