How Can I Make a Heat Pack to Ship Fish In Cold Weather?

Shipping fish in cold weather is easy with the proper preparation and care. In freezing weather, all fish will need a heat pack in the box, even cold water species like goldfish. You can purchase heat packs or make your own from some simple household ingredients. When using heat packs for shipping fish, whether they are homemade or store-bought, place the heat pack on top of the fish container to allow heat to vent from the box.

Things You'll Need

  • Sock
  • Dried beans
  • Cardboard shipping box
  • Styrofoam sheets
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Instructions

    • 1

      Fill a sock with dried beans. How much depends on the size of the box you are using, but approximately one cup of beans is a good start. The more beans you use, the greater the thermal mass of the heating pack will be and the longer it will retain heat.

    • 2

      Line all six sides of the shipping box with Styrofoam boards. Boards are better insulators than packing peanuts or shredded paper. Use shredded paper inside the boards to keep the fish bag from rolling around in the box.

    • 3

      Microwave the sock and beans for one minute. Exactly how much time will depend on your microwave and how many beans you have in the sock. Start with less time and add about 15 seconds more if it is not hot enough.

    • 4

      Test your heat pack for shipping by placing a bag of water in the shipping container, setting the heat pack on top of the bag, sealing the box and leaving it outside in cold weather. Test different time periods to see how cold the water becomes. If you plan on shipping overnight, test for around 10 hours in the cold. Different species of fish have different water temperature tolerances. After leaving the bag in the cold, test the water temperature. If it is still within the tolerance range for the fish, you should be able to ship safely.