How Do I Disinfect an Aquarium?

Aquarium disinfection may become necessary when harmful bacteria are present in the tank. The evidence shows up on the fish, which will develop white spots or other visual abnormalities. There are a few different methods for fish tank disinfection, but the most common are chlorine bleach and methylene blue. When disinfecting with chlorine bleach, the tank must be completely emptied first. However, methylene blue drops can be added into the tank with the fish still inside.

Things You'll Need

  • Disinfectant (chlorine bleach or methylene blue)
  • Bucket
  • Sponge
  • Disposable gloves
  • Protective eyewear
  • Chlorine/chloramine removal drops
  • Replacement filter (if the tank has a filter present)
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Instructions

  1. Disinfecting with bleach

    • 1

      Put on protective glasses and gloves. Transfer the fish to another tank or holding container, and remove all gravel and decorations from the tank.

    • 2

      Add one cup of bleach and 19 cups of water to a bucket to prepare a 1:20 dilution of bleach solution.

    • 3

      Remove all water from the tank, and pour the diluted bleach solution into the tank. Thoroughly wash the tank and remove any residue from the glass.

    • 4

      Empty the bleach solution from the tank into a bucket, and use it to wash all decorations and gravel. Also use the solution to disinfect any tubing or other equipment that comes into contact with the fish tank. This includes nets, filters, air bubblers and tubing.

    • 5

      Rinse the tank, gravel, decorations and other bleached equipment with tap water to remove any residual bleach solution.

    • 6

      Replace the gravel and decorations in the tank, and refill it with water.

    • 7

      Add chlorine/chloramine removal drops to the tank water to cure the water of any residual chlorine bleach and the chlorine from the tap water. Change the filter and allow the tank to cycle for six to 24 hours before adding fish.

    Disinfecting with methylene blue

    • 8

      Add 1 teaspoon of methylene blue for every 10 gallons of tank water for treatment every other day for 10 days.

    • 9

      Check the general appearance of the fish and determine if any signs of illness are still present. If additional treatment is required, follow the same regimen for 10 additional days.

    • 10

      Drop one dose of methylene blue into the tank once every other week as a preventative treatment.