How to Clean a Fish Tank After a Disease

After a disease breaks out in your aquarium, you must sanitize and clean the habitat before reintroducing fish. In cases of a minor disease outbreak in your tank, your best option involves sanitizing with a saltwater solution. In more severe cases where a disease has wiped out the inhabitants of the entire tank, sanitizing with a bleach solution is often the better option. Some disease pathogens have a hard outer shell that only bleach can kill.

Things You'll Need

  • Salt
  • Bleach
  • Dechlorinator
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Instructions

  1. Salt Method

    • 1

      Add 2/3 cup salt for each gallon of water in your tank. For example, if your tank holds 30 gallons, you'll need 20 cups of salt.

    • 2

      Swish the salt around, checking to ensure it completely dissolves.

    • 3

      Allow the tank to sit with the saltwater solution for a minimum of 30 minutes. If you don't need to reuse the aquarium right away, let the solution work for two to three days for best results.

    • 4

      Rinse the aquarium thoroughly with clean fresh water.

    Bleach Method

    • 5

      Add bleach to the aquarium in a 20-to-1 ratio of water to bleach. For example, if your aquarium holds 20 gallons, add 1 gallon of bleach to the 20 gallons of water.

    • 6

      Turn on your filtration system, and allow the tank to filter this bleach solution for 24 to 48 hours.

    • 7

      Rinse the aquarium thoroughly with clean fresh water.

    • 8

      Add a dechlorinator to the tank before reintroducing fish. The required amount will vary depending on the product; read the instructions on your product's label. Dechlorinators work quickly, so you can reintroduce fish into the tank after waiting two to five minutes.