How to Keep a Goldfish Tank Clean

Goldfish tanks are cleaner when they are not overcrowded.

Goldfish tanks are cleaner when they are not overcrowded.

Tank cleanliness doesn't just affect the appearance of your goldfish habitat; it can also affect fish health. A cloudy, dirty tank increases your fish's susceptibility to disease, parasites, fungal infections and behavioral problems. With a few basic maintenance steps, however, you can easily keep your tank sparkling.

Use a water filter in your goldfish tank. This will greatly increase the time you can go between water changes. Pick a filter designed for the tank size you have. For example, a 10-gallon tank requires a 10-gallon filter. Change the filter cartridge according to the package instructions, and clean the filter itself with warm water every two to three months.

Change 10 percent of the water in the aquarium every week. Using an aquarium vacuum, suck out the old water into a bucket. Use the vacuum to suck debris out of the gravel at the bottom of the tank by running it along the gravel. Then replace the water with clean tap water treated with a dechlorinating treatment safe for goldfish. Follow the directions on the dechlorinator package.

Use a tank clarifying treatment to increase the cleanliness of tank water. These treatments bind to debris and either disintegrate them or lower them to the floor of the tank, making it easier for an aquarium vacuum to pick them up.

Items you will need

  • Filter
  • Aquarium vacuum
  • Bucket
  • Dechlorinator
  • Tank clarifier


  • Live aquarium plants can increase the oxygen level in your tank and decrease debris.
  • Algae eaters will consume excess algae if your tank is dirty due to an overgrowth.
  • Feed your goldfish only as much food as they can eat in 15 minutes. Overfeeding can cause dirty water.


  • Avoid overcrowding. You should have five to 10 gallons of water per goldfish. Overcrowding can cause a variety of health problems as well as dirty water.
  • Since some algae eaters are aggressive towards goldfish, consult with a professional aquarist before adding them to your tank.

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About the Author

Brenna Davis is a professional writer who covers parenting, pets, health and legal topics. Her articles have appeared in a variety of newspapers and magazines as well as on websites. She is a court-appointed special advocate and is certified in crisis counseling and child and infant nutrition. She holds degrees in developmental psychology and philosophy from Georgia State University.

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