sometimes ive noticed they just don't feel like eating, my pastel wont eat unless its 5 days, its a youngun so i will throw the hopper in the night before so on 4 days and then hell just go over and basically sniff it and lose interest, then on day 5 BAM

just take the mouse back out of the cage and wait another day, keep tryin every day

and of course make sure husbandry is proper, 78-82 on one side, 88-94 on the hot side, try to provide two EQUAL sized hides so they dnt have to chose between security and temp. because they will..bleh. and he should eat

also check humidity 40-50 percent.

thats my 2 cents on basic ball behavior, ive also noticed that pastels act REALLY weird compared to normals, the one that i have and others i have handles do anyways. so dnt give up on the little feller! plz lemme know how it goes!