How to Replace Gravel in a Fish Tank

Replacing gravel in an established fish tank is a job that will take some time to perform and must be done properly to ensure that no harm comes to your fish or other aquatic life. If you are replacing the gravel in a fish tank due to unsanitary aquarium conditions, this task may take longer than if you are simply replacing the gravel in the tank for aesthetic reasons.

Things You'll Need

  • Temporary holding tank
  • Gravel
  • Aerator
  • Dechlorinating agent
  • Fish net
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Instructions

  1. Dirty Aquariums

    • 1

      Fill an empty aquarium half-way with water from the dirty aquarium. Fill the container the rest of the way with clean water.

    • 2

      Add a dechlorinating agent to the aquarium, and place an aerator in the tank to provide air for the fish while you are cleaning the original tank. Place the fish into the temporary aquarium.

    • 3

      Empty the remaining water from the dirty aquarium and discard.

    • 4

      Scoop out one to two cups of the old gravel and place aside. Aquarium gravel contains a beneficial bacterium that is essential to a healthy fish tank even when it is dirty, so it is important to reserve some of the old gravel to help re-colonize the bacteria in your fish tank once it is clean.

    • 5

      Remove the rest of the gravel from the dirty fish aquarium and discard. Clean the inside of the aquarium using only hot water and a clean sponge or rag.

    • 6

      Rinse the new gravel you will be using as a replacement under hot water to remove dirt, dust and debris.

    • 7

      Place the new gravel into the aquarium, adding in the reserved gravel from the old tank. Continue to set up your aquarium following procedures for a new tank set-up.

    Clean Aquariums

    • 8

      Drain a few inches of water from the clean fish aquarium to prevent over-spill when removing gravel.

    • 9

      Use a small net to slowly work at scooping out the existing gravel. Remove the gravel slowly and gently to prevent scaring and stressing the fish.

    • 10

      Leave one to two cups of the old gravel in the clean fish aquarium so that the friendly bacteria living in the gravel can help to re-colonize the tank when the new gravel is added.

    • 11

      Rinse the new gravel in hot water to remove dusty debris. Pour the new gravel into the clean fish aquarium one scoop at a time, using a net or your hands to smooth and level the new gravel on the bottom of the tank.

    • 12

      Add a small amount of dechlorinating agent to the water to compensate for any chlorine residue that may remain on the new gravel from rinsing with chlorinated tap water.