Before I got him, he was eating fully lively live medium rats. I want to switch him to pre killed. You're right, if he's showing interest that might be a good sign... I have had all four sides and part of his lid covered in black paper. And it's been tough to let him be, but I have been really good...
I have another boy, and he will eat anything I put in his tank, so if the live ones aren't eaten I just kill them and freeze them for him. He doesn't even coil if they're not moving, just start munching on their heads...