Join Date: Feb 2012
Location: Ontario, Canada
Not sure about styrofoam boxes, but coolers and cooler bags are a great idea! Also make sure you place them in the most sturdy place possible in the car, likely the floor of the vehicle. Seats and the trunk are places they'll move around in, and places their water will move around most too due to turns, torsion, etc. Keep in mind everything in the car is moving at the same speed as the car itself too - this is why sudden stops hurt for people - they also hurt for fish, who will slam into the sides of the container. Remind whoever is driving to accelerate and slow down smoothly, try to avoid sudden stops, and to also try to avoid bumps and tight turns at too fast a speed (I know, where's the fun in driving like that? haha). But it will make a big difference for your fish :) Also keep thermometers in their containers, so you can monitor any large fluctuations throughout the trip and try to correct them if necessary. They should be OK, although a little stressed, between temps of 60 - 85 ish.
Also set them down within the house to stabilize and get their "feet back on the ground" for at least half an hour - 2 hours once you arrive at your destination, before putting them in a new tank. And keep them in a dark space for the duration of the move and at least 24 hours after moving them. When it is time to turn the lights back on, do it gently by exposing them to the room lights only, and then tank lights. (I realize they'll see room lights at periods where you change water and first move in, but do try to keep this as a minimum, as it actually confuses them more. If they just think it's night the whole time, they'll relax and sleep a bit).
Best of luck with the move! I hope everything runs smoothly.
EDIT: It also sounds weird, but don't forget to try and move as much of their original tank water as possible! It will help when you acclimate them to the water in the new area, so that the water in the new location doesn't shock them when their tanks are set up.