I often get asked about how i pack fish for posting ... well, here it is!
1. Find a suitable box with ample room for the fish, insulation and heatpack or use a polybox.
2. Fish bags... I use 4" bags for my bettas, most people use larger sizes but I prefer these smaller bags due to the less water movement created..if you use kordon breathable bags bettas still need the air pocket!
3. I use fresh water for shipping... i float a 2ltr bottle overnight in the tank to get it to temp. I add aquasafe, few drops of stress coat, pinch of salt and few drops of weekly cleaner(like safestart) to help keep waste levels to minimun.. Fish are also not fed on posting day.
[You must be registered and logged in to see this image.]4. Fish are then transferred into the clean water and double bagged. First bag containing fish is placed upside down into a second bag then bag corners are folded before sealing 2nd one to ensure the fish can't get stuck plus the extra security of two bags incase one leaks. Ensure the bag can be turned anyway up and the fish still has ample water and always leave a decent airpocket.
[You must be registered and logged in to see this image.]5. Fish bubble is then rolled in bubblewrap for extra security.
[You must be registered and logged in to see this image.]6. Box is lined with bubble wrap, foam chips and or newspaper, the best of what I have to hand and in go the fish, ensure ample insulation from box walls on all sides. The packing wants to be tight enough to prevent movement of bags but not enough to put pressure on them.
[You must be registered and logged in to see this image.][You must be registered and logged in to see this image.]7. A layer of scrunched newspaper goes on to to give insulation from the heatpack (you want the heatpack to maintain temp in box not burn the fish).
8. Open a fresh heatpack and activate it by shaking ...don't get it wet!!!
Now wrap this a sheet of newspaper and place in top of box
[You must be registered and logged in to see this image.][You must be registered and logged in to see this image.][You must be registered and logged in to see this image.]9. Securely tape up the box, add fragile labels, this side up etc.
Put senders address on near the bottom of box and recipients address on top .. leave ample room for the special delivery and postage stickers to ensure they always go on top of box where heatpack is.
[You must be registered and logged in to see this image.]10. Take to post office and pray the posties are good.

I always email the buyer with the tracking number so they know the fish are definately posted and on the way.