Yeah Polys are fish you don't too frequently hear about starving to death. Just give him a variety of food and when he gets hungry enough he's bound to eat something.
I do not see my bichirs eat much at all. I know they do, but I never see it. I do my feedings a couple hours after the light goes out. The food is always gone in the morning and they grow like weeds. I have done this process from 2-3 inches up to my 12" Ornate. I have never had a hungry bichir.