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How to clean a fish tank

How to clean a fish tank
(Image credit: Getty Images)

You've got a fish, you've got a tank, and now you're wondering how to clean a fish tank. Don't worry, it's not all that difficult to clean a fish tank, and there are different ways to approach cleaning it, as well as some things you should use to clean your fish tank and some things you should avoid (we've got best fish tank cleaners to help you with that even more). There are multiple elements in a fish tank, and we'll walk you through how to clean them all, from the gravel to filter to the glass.

If you've gotten a tank from our best fish tank list, you'll want to take care of it. Plus, cleaning a fish tank is an important part of keeping your fish healthy. When the water in a fish tank becomes dirty, your fish are more likely to get stressed and are more likely to fall ill. Cleaning a fish tank is an important part of being a fish parent, so we'll walk you through every step.

 What to clean a fish tank with 

In order to clean a fish tank you'll want to make sure you have a safe fish tank cleaner that won't harm your fish. You'll need multiple products, as fish tanks have multiple elements. That means you'll need a cleaner that tackles algae, a glass cleaner, a product for gravel, and a filter cleaner.

Here's a complete list of items you'll need to properly clean your fish tank:

  • Algae cleaner/scraper
  • Gravel vacuum
  • Bucket
  • Lime remover or aquarium-safe glass cleaner
  • Old bath towels
  • Paper towels
  • Filter brush
  • Chlorine remover

How to clean a fish tank

(Image credit: Getty Images)

 How to clean fish tank gravel 

You'll want to use a water siphon to vacuum up any debris in the gravel. The siphon moves the gravel around and vacuums up and debris kicked up without vacuuming up the gravel. The siphon will replace the water removed with dechlorinated water, which helps swap out some of the water in the tank. Make sure it's the same temperature as your aquarium water, and make sure your heater is unplugged during the process. 

 How to clean a fish tank filter 

If you have filter media that contains carbon, ammonia absorbers, or ion-exchange resins, it should be replaced if it's more than three weeks old. If you have a filter that is mechanical and does not absorb toxins like a filter fiber, sponges, or a ceramic filter, you can gently rinse it and place it back in the filter. Clean the filter tubing and other parts of the filter that are in the tank's water with a filter brush. 

 How to clean fish tank glass 

Clean the interior glass with an algae pad you got at a pet store or online pet storefront like Chewy. Sometimes houseware algae pads can have soap or chemicals that can be lethal to your fish. 

If there are stubborn sections of algae residue stuck to the inside glass, you'll need to carefully scrape it off with a razor blade - if you have an acrylic tank, use a plastic razor blade, as normal ones will scratch the surface. 

If you want to reduce the amount of algae in your tank, you can use algae tablets to help control new growth and remove algae. HOWEVER you cannot use algae tablets if you have turtles or live plants. Double check that algae tablets are safe for all the creatures in your tank before using it. 

Steps to clean a fish tank

How to clean a fish tank

(Image credit: Getty Images)

It's easiest if you clean a fish tank in a particular order. Believe it or not, you can leave your fish in the tank while you clean it - removing them from the tank can stress them out, and you could accidentally injure them. You don't need to fully drain the tank of water, so the fish can remain - plus, completely replacing the water in the tank can shock your fish. 

Cleaning your fish tank in a particular order will make the process easier and more efficient and will also decrease the likelihood of you disturbing your fish or accidentally upending the balance of bacteria in the tank's water. There is beneficial bacteria inside fish tanks that should remain there, and doing things like cleaning a filter at the same time you clean your entire tank can trigger an ammonia spike, which can be fatal for fish.

Here are the steps you should follow when cleaning your fish tank:

1. Clean inside glass

As detailed above, clean the inside glass with an algae pad and razor blade.

2. Clean decorations and plants

After cleaning the interior glass, you'll want to take out any decorative rocks, fake plants, or other decorations that have noticeable algae growth or are otherwise obviously dirty. It's important that you do not clean anything in your fish tank with soap, as it's almost impossible to completely remove soap which can have harmful side effects for fish.

Using an algae scraper in warm water can effectively clean decorations and artificial plants. You can use a 10% bleach and water solution to soak particularly dirty decorations, but you'll need to rinse thoroughly in water after and air dry to try and eliminate as much bleach as possible. If they still smell like bleach or chlorine, do not put them back in the tank. You can bleach live plants as well in a 5% bleach solution, but stem plants can't handle bleach.

3. Clean gravel 

Clean the gravel using the water siphon technique discussed above. Make sure to keep all the decorations, plants, and rocks outside of the tank while vacuuming the gravel. 

4. Clean outside glass

Only use aquarium safe cleaners to clean the outside glass and tank fixtures, as ammonia is very toxic to fish. You can also use vinegar. When cleaning the glass and other fixtures, make sure to clean the hood, light, and top of the tank as well. Then go over everything you've cleaned with damp cloth or wet paper towel. 

5. Wait two weeks after a tank clean to clean the filter

You'll want to wait to clean the filter until two weeks after you cleaned all of the other fish tank elements. Not waiting can further disturb the tank's bacteria, much of which is beneficial for your fish.