How To Properly Clean Your Fish Tank

Having an aquarium is a great way to decorate your living room and make your place more interesting and attractive. That’s why many people choose fish when they visit a pet store. Plus, they look really cute, don’t you think? 

A beautiful fish tank in a living room

However, like all pets, fish need care and attention. Unfortunately, fish treatment is a little more complicated than what a dog needs. You can’t just put your fish on the leash and take them out for a walk. There are several things you should do to keep the fish tank clean and your fish happy and healthy

Metabolites and nitrates that build up over time and the algae layer on the glass can affect both the health of your fish and the appearance of the tank. You should absolutely remove algae once you see it. Even if you have a filter to keep the water clean isn’t enough. And just rinsing it or cleaning it with paper towels just won’t work! Many things should be done so everybody will be happy. So, here’s a step-by-step guide with all relative information about how to clean your aquarium

Why do you need to clean your fish tank?

Cleaning your fish tank and changing the water on a regular basis is important for the well-being of your fish. 

  1. You will maintain a healthy environment for your fish, by reducing all harmful agents like ammonia, nitrite and nitrate. All these, when they exist in high levels into your aquarium can make fish ill, blocking their growth and colour development.
  2. The decaying of organic waste releases toxic nitrogenous compounds, reducing water quality. This creates an acidic environment which can affect the buffering capacity and the pH of the water. 
  3. Changing the water regularly will provide all the necessary nutrients, minerals and vitamins for your fish to grow. 

How often should you clean your fish tank?

There isn’t a rule of thumb about how often you should clean the tank. Many factors determine the frequency, like the size of the tank, the number and the type of the fish and whether or not there’s a filter system. But, you can keep a general cleaning program that will help you maintain your aquarium safe for your fish.

A man cleaning the inside of a fish tank

Daily cleaning

You don’t have to clean the tank on a daily basis. However, you can watch your fish for a while to notice any behaviour changes. If for example, they’re breathing normally or they’re moving slowly, then it’s probably time to do a partial water change, even if you had changed it not so long ago.

Weekly cleaning

Having a large tank, it’ll save you from having to keep a weekly cleaning schedule. If you have an average-sized tank though, then a weekly water change is essential for their health. Just replace a quarter of water from the tank with treated water. Use a sponge to clean any decoratives you may have inside and vacuum the gravel using your aquarium vacuum to remove any debris. 

Monthly cleaning

When it comes to monthly cleaning, you should check the ammonia, nitrate and pH levels in the tank and keep them in a sufficient condition. A good idea would be to write them down every month to compare the changes and act accordingly whenever there’s a difference. What’s more, a filter cartridge cleaning should be included in your monthly cleaning program.

A twice a year cleaning 

Every six months you should give a more thorough and deep cleaning to your tank, including decoratives, filters, pumps, lights and so on. You should replace anything broken and remove dust, dirt and debris using the right remover tools. 

How to clean the inside of your tank

The best way to clean your tank is to start cleaning first the inside of it and then moving on to the other parts. To begin with the process, you should first unplug the heater, the filter and the air plug. Then, remove the fish and any artificial plants and decorations of the tank and empty the water. Now you’re ready to start cleaning.

A man taking out the water from a fish tank

Let’s see what you’ll need to clean the inside. 

  • A clean cloth
  • An algae pad/magnet or scraper
  • A bucket
  • A siphon
  • A gravel vacuum
  • A bucket 
  • A thermometer
  • Water conditioner
  • Aquarium salt

Here are the steps you should take:

  1. Start by cleaning the inner glass sides of the aquarium. Use the algae pad to scrub gentle the glass and remove any algae. 
  2. It’s time to change the water. Use the siphon and remove the water into a bucket. You should remove up to 50% of the tank water. 
  3. Now, use the gravel vacuum to remove any debris and uneaten food. 
  4. Check the filter cartridge and rinse it if it’s too dirty. 
  5. Now, everything is ready to fill the tank with freshwater. Replace the aquarium water with fresh at the temperature of the tank. Use the thermometer to be sure about the right temperature. In case you use tap water, add the conditioner and salt to remove any heavy metals. Wait a few hours to dissipate any cloudiness before adding your fish back to the freshwater aquarium.

Note: Avoid using any sponges from your kitchen sink. They might have any residue detergent that can harm your fish.

Extra tip: You can use a toothbrush to clean any patches of dirt left. 

How to clean the outside of your tank

Since you’ve finished cleaning the inside of your tank, which is the most complicated of all, it’s time to clean the outside, which will be a piece of cake. The exterior includes apart from the glass, the hood, the light and the lid as well.

A man cleaning the outside of a fish tank

For its proper cleaning you’re going to need:

  • An aquarium safe glass cleaner (or instead you can use white vinegar as a more natural option)
  • Clean cloths

Once you’ve gathered all the needed materials, follow these simple steps:

  1. Spray the cleaner onto the cloth and wipe down the glass. 
  2. Use a second clean cloth to dust the lid, the hood and all the other external compartments
  3. Use a damp cloth to rinse all the surfaces

Extra tip: If you have an acrylic tank, then you can apply a special polish on the outside glass.

Note: Avoid spraying the cleaner directly onto the glass, as it might get inside the tank or the water and harm your fish. 

How to clean decorations & rocks

When you remove the decorations, artificial plants or any rocks you may have decorated your aquarium with, you should clean them as well before you put them back in place as they collect algae and dirt. Avoid cleaning the decorations with soap and detergents because even a trace can put your fish in danger. 

To properly clean them, you’ll need:

  • An algae scraper
  • Warm water


  1. Soak them in warm water for a while and scrub them. 

For any stubborn stains, you better use:

  • A bucket
  • ¼ cup of bleach
  • Clean Water
  • Dechlorinator

Now, do as follows:

  1. Fill the bucket with clean water, add ¼ cup of bleach and soak the decorations for 15 minutes
  2. Afterwards, rinse them thoroughly with new water very well. To make sure that there is no residue left, you can even let them air dry. For even better results, rinse the items in water that has a de-chlorinator to remove any chlorine. 
  3. After they are dry, put them back in the tank. 

Extra tip: Don’t use bleach or boiling water to clean the decoration and false plants, cause you’ll probably kill beneficial bacteria and poison your fish. Just use water to rinse them.

If, by the way, you have live plants in your aquarium, never remove them, because you’ll disturb the root growth. 

A woman taking out the decoratives from a fish tank

How to clean the filter

Once you’ve cleaned everything, you can put them back in place. Now, the time has come to deal with the filter. You just have to wait for a couple of weeks before you clean the filtration system not to disturb the aquarium’s ecosystem. Note that you should clean the filter at least once a month. 

How you’re going to clean the filter depends on the type of filter you have. There are two types, the corner box filter and a sponge filter. Both types are very easy to be cleaned, and you don’t need much to do. For both types, you’re going to need the bucket filled with the old tank water. It is strongly recommended not to use soap and other detergents for your fish safety. Plain water is just enough.

If you have a corner box filter, remove the filter and dip it into the bucket. Then, swirl it and wash it in the bucket. But, if you have a sponge filter, then you have to remove the foam part, soak it into the bucket and wring it out several times

Tips & warnings

  • You should always wash your hands before you start cleaning the tank and after finishing with the whole process.
  • Once you’ve finished cleaning, let the tools you used to soak in hot water for a while. This way, any bacteria left on them will be killed, and you’ll be able to store them.
  • If you want to remove your fish out of the tank, you better use a net to do so and not by using your bare hands; otherwise, you’ll probably stress your fish. Fill a bucket with the tank water, catch the fish with a net and put them into the bucket. 

Every time you refill the tank using water from the tap, you should let it sit for 24 hours, as it contains chlorine that needs to evaporate. However, instead of waiting for chlorine to evaporate, you can dechlorinate tap water by using a water conditioner.

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