If you expect to receive nighttime low temperatures in your area of less than 50 degrees F, please select this option. While our normal packaging includes heat packs, it is not designed to withstand temperatures below 50 degrees F. When this option is selected we will use a thick-wall styrofoam shipping box and a heat pack to ensure your new fish arrive to you safely. This up-charge is added to your shipping costs. If nighttime temperatures in your area are less than 50 degrees F and this option is not selected, our Live Arrival Guarantee will be voided. If temperatures are below 25 degrees F in your area, please consider waiting for warmer weather before you place your order.