BP are notorious picky eaters, wait a week and try again, maybe try a smaller mouse, he might have found it too big for his liking, go with a small mice and then see if after he eats he'll start to eat something bigger, it might just be stress because of his new habitat, let him get accustomed, dont stress out just yet, mine did that twice when i first got her before his hunger got the best of her =] good luck