Hi,
I feed crawdads or crayfish to my octopuses. I catch them by netting them out of a creek in Arizona. They are considered an introduced "exotic pest" in Arizona's lakes, streams, rivers, etc., and our state wildlife management division has an open bounty on them because their feeding habits reduce aquatic habitat quality causing demise to our popular sport fish populations. Anyways, they live in fresh and brackish water and look almost exactly like clawed lobsters. They have a hard exoskeleton, which they molt as they grow. I do remove their pinchers before feeding them to my octopuses, but I'm sure my octopuses could handle themselves if I left them on.
Here is what one looks like. I'll put up a better picture tomorrow of my "feeding tank" for you.
Regards,
Dr. Idso