How to Clean a Fish Tank After a Disease

Only reintroduce healthy and disease-free fish to the sanitized tank.

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

Instructions

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

1. 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.

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

3. Rinse the aquarium thoroughly with clean fresh water.

4. 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.

References

• American Aquarium Products: A Healthy Aquarium; Disease Prevention
• Hagen: Testing and Sanitizing a Used Aquarium