I just reviewed this posting an the original statement from Cecil included a warning that hauling fish is dangerous. As any trucker can tell you, liquid will slosh (bad spelling??) sideways, back and forward and can cause you to loose control on a curve. Going up and down hills can be a tiring experience. Put liquid in a trailer and you compound a bad situation.
Stopping is definately a new experience and the weight of the water hitting the front of the tank will always occur just when you are coming to the end of the road or at the stop sign. This can make even the bravest man's feet sweat.
You-ins with tanks may want to consider installing baffles or using multiple smaller tanks to minimize the danger.
Do not overload. If my memory serves me...water weighs 8 lbs per gallon and 64 lbs per cubic foot. Therefore, a small pick up size 6 by 3 by 3 tank completly full can be as heavy as 3,456 pounds not counting the weight of the tank and fish..... Put that in the back of a half ton (1000 lb) pickup and you have put yourself in great danger.