As someone who keeps isopods I can confirm they're every bit as food-aggressive as their shrimpy cousins. Anything dead or dying gets attacked viciously. One time I found a roach in the house and smacked it. Seems I broke it's back or something because it could still move it's front 2 legs but that was it.
I tossed it to the pillbugs and checked back after 20 minutes. It was struggling trying to push them away, but they were rapidly disassembling it. When I checked again a few hours later there was nothing left at all.
Here's a picture of them swarming a moth.