Make sure you have bags that are at least twice as tall as they are wide. 3 times taller is better, but just twice will work. I use Bag Buddies if Iím sending fish overnight, but I donít know that they are actually beneficial. If youíre just sending a few bags of fish, you can check with your local fish store, or even veterinarianís office for insulated boxes. Vaccines, frozen foods, and even other fish are routinely shipped around the country, and the boxes arenít too difficult to find, if you know where to look.
When I know Iím going to be shipping fish, I fast them for at least 24 hours. If the fish are adults and wonít be harmed by short rations for a few days, I try to make it 48 hours. This gives them a chance to clean out their systems and reduces the amount of waste and ammonia youíll get during shipment. It makes a huge difference in the stress levels youíll see in fish youíre shipping. I also try to do a water change of 30-40% on the tank that Iím going to be shipping fish out of, within 24 hours of packing them, for optimal water quality going into the bag. Some people use Ĺ or even more dechlorinated tap water when theyíre packing fish. I donít do that personally, as I tend to do frequent water changes anyway, but itís a method that people have good success with.
When you put the fish in water in the bag, be sure to put 1/3 water, 2/3 air. I always recommend at least double bagging fish, if not triple. When you set the first bag inside the second one, give it a Ĺ twist, so that the corners of the bags are now bunched up, to prevent fish getting trapped in them during shipment. Keep in mind that if your fish are going to travel as air freight, there will be some expansion in the bags, due to cabin pressure changes, so donít pack them too tightly. I love to see the bags nice and drum tight, so it was a bit of trial and error before I realized what I was doing wrong. Once you have the bags packed in the cooler, surrounding them with packing peanuts or other packing media (thatís not going to soak up water) will help stabilize the bags so they arenít being tossed about inside the box.
If youíre going to use heat packs (which I recommend if the ambient temperature is less than 70 degrees F), keep in mind that they are air activated. Tape the edges of the pack to the lid of the box, but do NOT wrap them in paper towels, newspapers or the like. If you want a buffer between the heat pack and the bags, lay it on top of the bags. I tend to use a larger box liner, fill it with the bags of fish, then fold that liner over the bags a few times and tape. That way, if you do have a bag that leaks, the water will hopefully stay in the box long enough to keep the fish alive until it can be unpacked.
Good luck shipping your fish!