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In order to the clean the tank you will need a net to safely remove the fish, a vacuum or siphon to remove the debris, and a five gallon bucket to change the water. You do not need to remove the fish from the water each time you clean the tank. It is best if you can try to keep the fish inside the water while you clean it. If you need to remove the fish, then use the net to transfer them to a large container. Make sure the water is de-chlorinated before placing the fish in the temporary container. You will need to vacuum or siphon feces and debris from the tank at least once a week. Use a siphon to remove the debris. If you have gravel in your tank, run the vacuum over the top of the gravel. If you have sand, hold the vacuum slightly above the sand to avoid dispersing and/or sucking up the sand. You will also need to change the water once a week. Use a five-gallon pitcher to remove and replace the water. Replace a third of the water with fresh water each week. If algae is growing on the tank’s walls, then clean and remove this, as well. Use a clean rag to remove the algae. If the fish is attempting to get past your hand and nip the rag you can use an algae scrubber, which you can buy online or at your local pet store (Or Fish Market.)

Summary:
Purchase the cleaning materials. Vacuum the tank. Change the water.