what size tank are you putting him in man?
and also find out what he was being fed before you buy him, if he is on feeders you may have to ween him back to shrimp or beef heart. unless you are already stocking your tank with a supply of feeders.
Other than that give him a place to hide during the day.
I hope you are ready! I love the royals and clown knives the most i think, so good luck with your new addition