i am moving 2 fancy goldfish from their tank into a tank that housed 2 other goldfish who are moving to a . .?

You should treat the move like a normal weekly water change and change the filters too. That way any parasites or disease that MIGHT be in your tank will either be killed or elimanated. You should also replace some but not all the water with some of the old water, that way you minimize stress and the risk of toxic shock

First you need to put the fish you are moving in plastic bags with water from the old tank and plenty of air. Place bags in water of new tank and let set for approx. 45 minutes to an hour so the water in the bag and the water in tank are the same tempature. Then slowly release fish out of bag into water so they get shocked by the new water.

I would also put the two fish in a bowl of water with half of their original water and half of the new water from the tank that they will be going into (for about 20 minutes), to help them adjust to any differences in the water. Don't forget to cover the bowl they sometimes jump. Good luck.

after CHANGING the carbon filters, change out about 1/3 of the water.. that will refresh the tank nicely. That is all you really need to do.

Nancy is right...you may want to change 1/3rd of the water, and put in a little of theirs when you transfer them.

Good luck.