Hi and welcome! Very nice looking snake you got there. I've offered F/T to my two newest arrivals just 2 days after receiving them - both had been eating live previously, and both took it no problem. So, you could offer what you'd like to be feeding him, and if he refuses, wait a few more days and offer whatever he's been being fed....or you could play it safe and start off with what you know he's been taking. Good luck!