I've been using raw prawns for 10 or 15 years. I bag them in small freezer bags, about six or eight per bag, and have them ready to go in the freezer. I pull them out in the morning. They thaw pretty fast. After fishing, if there's any left (4 prawns is enough for a typical day), it's back in the freezer. You only want a small piece hooked and egg looped as it's the scent that attracts them and small means your offering is drifting naturally. The best are the Tiger prawns. Wait for a sale and see if they have any that aren't de-veined.