1. We use Uline insulated shipping kits.
Link:
http://www.uline.com/BL_2157/Insulated-Shipping-Kits2. 3 mil bags, double or triple bagged depending on size/type of fish ans we fill the bags with pure oxygen(O2). 1/3rd of the bag with water rest with O2 and then a clamp or most people use a few rubberbands to "tie" the bags.
Link:
http://www.uline.com/BL_114/3-Mil-Poly-Bags3. UniHeat packs, usually the 40 or 72 hour pack depending if shipment is local or overseas.
Link:
http://www.pangeareptile.com/store/40-hour-heat-pack.htmlJust use ice in ziplock freezer bag
4. Various bubble wrap, packing peanuts, or even old newspaper to fill a void.
5. Fed Ex, UPS, or someitimes depending on weight the US Postal Service. All depends on when it needs to be there and where the package is going. All 3 services have their good and bad points. You just have to really experiment with each and see what you and your customers feel comfortable with.