1. You should feed your fish a variety of food and not just flake foods. Mix it up with fresher foods from their regular diet. Giving them more a varied diet will increase the general health of your fish.
2. You should take out any carbon filters in the aquarium when you are medicating your fish. The carbon in the filter will remove the medicine from the water, so it is best to remove it all together.
3. If you have a protein skimmer you should shut it off when you are adding medicine to your aquarium. The protein skimmer will remove any medicines added to the aquarium.