I've never shipped anything, but I have taken corals on a plane ride with me. We live in No. VA and I was working in Colo. Springs. Found some corals (a bubble, toadstool, and some zoos), purchased a small cooler and some heat packs (hand warmers) from Target and had them in the cooler for approx. 12 hrs. or so. All made it fine and look great to this day. This was during early April, so I felt that the heat pack were neccessary, but I also fly a lot and it can get chilly in the cabin during high summer, let alone in a FedEx cargo plane. At 30K feet, its pretty cold. Anyway, if your shipping a fair distance, I suggest some sort of warming device to keep the temp a little more constant. A short distance may not be too bad, but definitely use a small cooler or thermos or whatever to try to keep the temp as constant as possible. I also used paking peanuts to keep them from shifting too much and I figured they would also help with insulation. HTH.