Bacteria in your fish tank can cause life-threatening illnesses in your fish. Evidence that your tank has too much bacteria include murky tank water and visible signs of illness in the fish (e.g. white spots). If you observe any of these symptoms, it is important that you disinfect the aquarium immediately.
Aquarium Disinfection with Chlorine Bleach vs. Other Methods
Chorine bleach is among the most common methods for disinfecting a fish tank. Disinfecting a fish tank with methylene blue is another commonly used procedure. The primary difference between using methylene blue and chlorine bleach is in the intensity and speed of the disinfection. Chlorine bleach disinfection requires that the fish and water be removed from the aquarium, while the methylene blue disinfection is done with everything still in the tank.
Gather Supplies
You will need chlorine bleach, chlorine/chloramine removal drops, a replacement filter (if applicable), protective goggles or glasses, disposable gloves, a sponge, a measuring cup, and a bucket to perform the procedure. Always be sure to wear personal protective equipment (gloves and goggles) over the hands and eyes when using caustic chemicals, such as chlorine bleach. You may also wish to wear an apron to protect clothing from the bleach.
Prepare the Tank for Disinfection
Remove the fish and all fixtures, including any gravel, plants or other decorations from the tank. You can put the fish into a holding container or plastic bag while the procedure is performed. Also remove all of the water from the tank.
Mix Chlorine Bleach Disinfectant Solution and Disinfect the Tank
Prepare a 1:20 dilution of chlorine bleach by mixing together one cup of bleach with 19 cups of tap water in the bucket. Pour the bleach solution into the aquarium, and begin to clean the tank using the sponge. Be sure to wear gloves during this procedure. Continue cleaning the tank until all surfaces are free of visible debris.
Next, remove the bleach solution from the tank and place it back into the bucket. If the tank is large, use a measuring cup or other dipper to remove the bulk of the solution. Use the solution in the bucket to disinfect the fixtures (gravel, decorations and tubing) from the tank. Also be sure to disinfect the tools used in the tank, such as nets, air bubblers, and other apparatus.
Rinse the Tank and Return the Fish and Decorations to the Aquarium
Use tap water to rinse the tank and fixtures as thoroughly as possible. Next, replace the decorations, and refill the tank. Follow the procedures you used to setup the tank for the first time. Be sure to add chlorine/chloramine removal drops to the water and other preparation agents as necessary. Also replace the tank filter, and let the aquarium cycle for 6 - 24 hours before returning the fish.
Observe Results and Perform Preventative Maintenance
After 10 days observe the results of the disinfection. Have all of the symptoms cleared up? If so, then add methylene blue to the tank every other week as preventative maintenance. If the tank continues to have problems, consider performing disinfection of the tank with methylene blue.
Sources:
ASPCA: Aquarium care instructions (accessed 8/30/2010)
Americanaquariumproducts.com: Parasite and chemical treatments for fish tanks (accessed 8/30/2010)
Cheri Pearson - Cheri Pearson is a seasoned freelance journalist who holds a Bachelor's degree in Business Administration from the University of ...
