Live bloodworms (Chironomid midge larvae) have a hard head and sharp jaws. The head does not get digested and can cause a blockage in a fish's digestive tract. This is more of an issue with small fish or fishes that swallow their food whole. And the jaws can damage the digestive tract. There were also reports of the bloodworms remaining alive inside the fish for a short time and biting holes in the stomach lining, thus killing the fish.What would be the problem with bloodworms, exactly, that doesn't apply to other larvae? Or this would be applied to other aquatic larvae?