I agree with Alexandra. I'd go ahead and try f/t first. He may eat it easily and then you'll know it's not a worry. If he refuses...then I'd wait a week and try again with the live prey he's used to. If he eats live a time or two for you, then you'll know he's comfortable enough to eat and just might be stubborn about switching over...which you can work with. If he refuses the live offering as well, then you'll know that it might not be the prey type at all that is throwing him off and you should investigate your husbandry.