Moving Your Fish When You Move from Here to There

Here's what you'll need: a container, some trash bags, and some rubber bands. Here are more details.

The container should be the right size. Not too small, or it will cramp the fish and not contain enough air. Not too big, or you may not have enough water to cover the fish. It's best, if the container is insulated.
Some plastic trash bags. Make sure they are big enough to fill the container, when you inflate them. The translucent trash bags are better because they allow you to see a little bit about what is going on inside the bag.
Some 1/4" thick rubber bands. You'll need these rubber bands to seal the bags.

Change 20% of the water in your aquarium each day for several days before you move.
Don't feed your fish anything for the last 48 hours Make sure there is no left over food of any kind in their home.
Do not feed your fish, while they are traveling. We want the water to stay as clean as possible.

Put one of the plastic bags inside the container. Then put another bag inside the first, so you have a double bag. that way if the first bag leaks, the second will hold the water. You might want to add a third bag inside the other two.

Get a clean pan and scoop water off the surface of your fish's home and pour it into the plastic bags inside the container. Use good clear water from the surface.
Move the fish from their home into the container. Large or aggressive fish should be packed one fish to a container. Don't crowd the fish. Less crowding will mean more surviving. Learn more in first-aquarium-secrets.

Set the container with the plastic bags, water, and fish on a table. It's good if there is air inside the inner-most bag, but try not to trap air between the layers of bags. Squeeze the top edges of the bags together in your hands. Now lessen the pressure and maybe gently poke a finger in the opening so it's about 1" in diameter.

Keep your mouth about 12 inches from this opening and blow air into the bag. Don't put your mouth right on the opening, because the air from your lungs contains excess carbon dioxide.

Fill the bag with air and then twist the top and fold it over. Make sure the sealed bag will fit into the container, so you can close the container. Also make sure the bags fill most of the space inside the container.

Close the container. It is best if there is no light inside the container during the trip. The fish will be less active in the dark.
Be sure to keep the container warm but not hot during the trip. Cooler water will slow the fish's metabolism, so the fish will produce less waste and keep the water cleaner.

If possible you should take 80% of the water from your fish's home with you when you move.

After your move, set the aquarium back up. Don't open the containers with the fish. But open the containers that have the extra water without any fish. Pour that water back into the aquarium, and let the aquarium's filter run for a couple of hours. Open the containers with fish. Pour the water and the fish into the aquarium, and top the aquarium up with at most 20% fresh tap water.