I throw all kinds of insects and vermin into the FW. We got nearly 2x annual rainfall average last year and the local frog population EXPLODED. You could just open up the back door and 8-10 2" went scurrying. The oscars and arowana were on a frog diet for almost three months
But I digress. I think the live insect etc found around the house should always end up as dinner.
this is news for me as i was told that the silk worms are not good for fish[can't remember the exact reason though].here in India maybe different variety i guess, pretty darn good if silkworms can be safely fed! good news!!