He looks like he could handle an adult mouse at that size, or a weanling rat, they are about the same size. He's a little thin so feeding him a decent sized prey item will help put some weight on him.
Congrats on pick him up, and congrats on getting him to eat, that's always good!
Thanks, yeah it was his first meal at home so I offered the fuzzies and he took them right away. So next meal I'm planning a delicious adult mouse mmmm!