How to Cycle a Tank With Goldfish

Owning an aquarium brings a piece of nature into your home. Hundreds of types of fish of different colors and sizes are available for you to buy and maintain in a home aquarium. Fish-keeping can be as simple or complex as you want it. You can have a single betta in a bowl on your desk or go full tilt and set up a 500 gallon reef tank in your living room. New tanks must be cycled before you add fish. The cycling process encourages the growth of beneficial bacteria necessary for the health of your fish. Freshwater enthusiasts can use goldfish to cycle their tanks.

Things You'll Need

  • Fish tank
  • Aquarium water conditioner
  • Water test kit
  • Tank decorations
  • Filter system
  • Goldfish
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Instructions

    • 1

      Clear a space for your aquarium. Rinse the tank and set it in place. Rinse the gravel and carefully pour it into the tank. Decorate the tank with whatever rocks and accessories you like.

    • 2

      Fill the tank with water. Turn on your tank filter. Treat the water in your tank with a water conditioner. Let the water circulate for a few minutes.

    • 3

      Check the tank to make sure the filter is working properly and that everything is as you want it (placement of decorations, etc.) Float the bag with your goldfish in the tank. Wait about 10 minutes. Start the cycling process by opening the bag and adding the goldfish to the tank.

    • 4

      Feed the goldfish one or two pinches of food every other day. Be careful not to overfeed them, this will throw off the cycling process. Using the water test kit, test the water every day for the first week, and every other day during the second week. There are a couple of different types of test kits each with its own procedures.The simplest type of kit uses pre-treated strips. Performing the test is as simple as dipping the strip into your tank for a few seconds. Remove the strip and let it air dry for a few minutes. As it dries the strip will turn different colors, each color corresponding to a different property of the water. Compare the colors on the stick with the colors on the chart (included with every stick kit) to get your readings.You should see a gradual rise in the level of ammonia. During the second week you should start seeing a decrease in ammonia and a rise in the level of nitrites in the tank.

    • 5

      Perform a 20 percent water change after the second week. Test the water every two or three days for another two weeks. By now, the nitrite level should be fairly high but declining as the nitrate level begins to rise. During the fourth week, you should see a major decrease in the nitrite level and an increase in the nitrate level.

    • 6

      Perform a 20 percent water change after the fourth week. Test the water. Ammonia and nitrite levels should be zero and the nitrate level should be 20 parts per million or less. If the ammonia and nitrite levels have not dropped to zero, perform a 10 percent water change. Continue to test the water every two or three days until the levels reach zero. The cycling process is now complete.