they can go a long time, a few months probally if it was previously healthy. try feeding other stuff, i've had like 10 newts and only one ate pellets, and not very often. they like moving stuff. in the wild they aren't going to eat newt pellets. it's normal for it not to be eating them. try feeding crickets, chopped up earthworms, mealworms, snails, bloodworms, briine shrimp...