Get hold of a large polystyrene box (your LFS should haveone) line it with newspaper, add a layer of polysyrene chips. bag you fish in fish bags about a third full of water and make sure you trap lots of air before closing. put this bag in another bag upside-down and seal that bag firmly. pack the fish in the box and surround them with more polysyrene chips then close up the box. they can be transported like this for upto 36 hours or so without too many problems.