Well, I have some red worms. He's interested, but I think they're still too big for him. I'd say the worms are about the same diameter as the snake, and about half his length.

I put one in last night, and he bit into it - then the worm kind of wrapped itself around the snake (I really need to name this thing), and the snake then backed off.

Just now, though, I tried cutting one up, and I got him to eat a fourth of one! So, that's some progress, I guess.