The following is only a guideline and how we send our fish by post. We have successfully sold fish on ebay etc and have only lost 1 fish by posting it.
We use Royal Mail Special Next Day by 1pm delivery to the mainland UK only and under their guidlines of what is acceptable to post fry are OK and can be sent legally as long as it is written on the box - I always write on each side of the box and the lid in thick black marker 'LIVE FISH FRY - FRAGILE - PLEASE HANDLE WITH CARE' and during the winter months I usually add 'PLEASE KEEP WARM'.
This postal service has proven to be very reliable but you do have to watch the weight as there is a giant price hike if you go over 2kg - £7.95 for up to 2kg to £19.45 for 2 to 10kg.
I always leave it till 4.30pm until I go to the PO (the latest time to accept the parcels for this service is 4.45pm) and have the labels written ready - this means the fish are in transit for the shortest time possible.
To post you will need:
A strong poly box or a cardboard box fully lined (including a top and base) with 1/2 to 1 inch thick polystyrene sheeting - poly boxes we get free from our LFS, cardboard boxes free from Tesco and poly sheeting is available at all DIY stores; Good quality bags - thicker and tall bags are better and we get ours from our LFS or ebay; Bubble wrap - free from Tesco Newspaper 24 hour Heat pad (cold weather only) - bought in bulk from ebay; Bag buddy tablets - were only available to buy from the USA and the cheapest we found were via: www.petswarehouse.com (put bag buddies into the search) but I believe there may be some on ebay occasionally.
Depending on the size of the fish, you need to put just enough water in the bag so that it covers the fish - water is heavy so only a minimum amount is needed and just before doing the bag up you put in a 1/4 of a bag buddy tablet (1 whole tablet treats 1 gallon).
We only use freshly dechlorinated and heavily aerated water and always double bag (I can't do the bags up I'm too cack handed so thats done by my other half) and he does them up with 3 elastic bands for each bag with as much air in as he can get.
To start packaging place a page or 2 of newspaper on the bottom of the box, then place a sheet of bubblewrap over that (in winter I put bubblewrap all around the edges of the box as well) then start standing the bags upright in the center and work your way outwards. All empty space has to be filled either with empty bags of air or bubblewrap (or both), then when the bags are secure place a layer of bubblewrap and a sheet of newspaper over the top. If you are enclosing a heatpad, open it 10 minutes before you load the box and sellotape it securely to the top of the lid - never place it directly on the bags as it will melt them.
When the box is fully packaged I usually place a printout of my address, the buyers address and an acclimatisation guide that I got from: http://www.tropicalfish4u.co.uk/acatalog/Acclimatisation_Guide.html in the top of the box then we tape up the box by sealing round the lid then around the whole box above and below the address panel. I use large print for the address and tape it to the lid and also write my address in black marker pen on 1 of the sides.
