How To Clean a Fish Tank – Gravel, Decoration & Change Aquarium Water

In this article, I will explain how to clean a fish tank. Fishes are our precious jewels and keeping them healthy is very important. They are very delicate and thus adequate care must be taken in caring for them and this covers cleaning their habitat – fish tank.

Cleaning your fish tank is very important because like every living thing, fishes release wastes which when accumulated increases bioload, making the water toxic for the fishes. Thus, if your fishes must stay healthy, you must pay special attention to the cleaning of their home and do it at the right time, with the right tools and in the right way.

How to clean a fish tank
Cleaning a fish tank

What is the right way to clean a fish tank?

The first step to getting it right is frequency. How often should you clean your fish tank? As often as a partial change of 10 to 20% of the water every 2 to 3 weeks for freshwater and 10% every week for saltwater.

This is dependent on the size of the tank and the number of fishes in it. If done correctly, this will help prevent a full water change. A full water change removes all the useful bacteria required to break down wastes created by the fish.

You can read on self cleaning fish tank here.

The second step to answering the question of how to clean a fish tank is the supplies for carrying out the cleaning. To properly and effectively clean your fish tank, you need the following supplies:

Siphon water out of a fish tank
Siphon water out of a fish tank


–    Water in the quantity required to make the replacement.

–    Algae pad.

–     A large bucket (larger than 5 gallons or 10 liters) for this purpose alone.

–    A siphon-type gravel vacuum.

–    Filter media – sponges, cartridges, carbon packets.

–    Vinegar-based solution or Aquarium-safe glass cleaner.

–    Bleach solution in a different container.

–    Metal or plastic razor blade (be careful with acrylic tanks, as they scratch easier).

For Saltwater you need also:

–    Salt mix.

–    Hygrometer

–    pH strips.

–    A refractometer

–    A thermometer.

Cleaning a fish tank

Once you have gotten all your supplies, you are ready to start cleaning. The fact that the supplies for cleaning a freshwater fish tank differ slightly from supplies used for cleaning a saltwater fish tank, is an indication that the steps will also differ slightly. Let’s get started.

Clean a fish tank glass
Cleaning fish tank glass

Cleaning a freshwater fish tank

Step 1 – Get rid of the algae.

Algae grow very fast on the insides of the tank walls and your first task is to remove them. To do this, use the algae pad to clean the inside wall of the tank. Scrub where necessary, if you experience any particularly difficult spot, use a razor or plastic blade to scrape it off gently from the tank.


I.    Use hand gloves to do the job, but be sure the gloves haven’t been treated with any chemical.

II.    Don’t improvise with your kitchen sponge, use only algae pad.

III.    You can wait to do this step after you have removed 10 to 20% of the water you hope to replace.

Step 2 – Remove the old water

Before you begin cleaning, you should already be sure how much water you want to remove. 10 to 20% on a regular basis is fine, but if you have a sick fish, 25 to 50% removal will do.

Start by siphoning the old water into the bucket dedicated for this purpose. Remember that this bucket to get a new bucket for this particular purpose only.

Step 3 – Gravel cleaning

To do this, using the vacuum, push through the gravel to suck out the waste,excessive food, and debris in the gravel. To prevent the vacuum from sucking out any small or delicate fish you may have, use a sock (that has never been worn) at the end of the siphon, but be sure that the mesh is large enough for the debris being sucked out.

Step 4 – Decoration cleaning

Algae also grow on tank decorations, so they need cleaning. Using the algae pad,clean the decorations in the water you siphoned out. Do not use soap or any chemical or soap for this purpose, as it will harm the fish (es).

Step 5 – Replace the freshwater

Its time to replace the old water you siphoned out with clean fresh water. Be conscious of the temperature of the water, as this is very vital to the health of the fish (es). To be sure, use a thermometer to monitor the temperature and be sure it is within the dictated temperature.

After you replace the water, you can consider adding aquarium salt for fresh water to prevent diseases and keep the fish healthy. Once this is done, watch the water for some hours to be sure the cloudiness dissipates.

Remember to leave space between the water level and the tank to allow for oxygen-carbon dioxide exchange for the fish as they breathe.

Step 6 – Clean the exterior of the tank

The exterior of the fish tank also needs cleaning. Clean it using aquarium-safe cleaners to wipe down the glass, tank top, light, and hood.

Step 7 – How to clean a fish tank filter?

Consider changing the filter cartridge monthly, as the carbon inside the cartridge can cause harm to the fish if left unchanged. You can rinse the cartridge during your weekly cleaning but do well to change at the end of the month.

Cleaning a saltwater fish tank

This is only slightly different from freshwater because it has some additional steps.

–    After cleaning the decorations, before replacing the saltwater, clean the salty creep with an algae sponge. Salty creep is the crusty residue that forms after saltwater evaporates at the top of the tank.

–    When replacing water back to the tank, it has to be a saltwater solution of the right salinity, pH and temperature.

Ultimately,to get it right on how to clean a fish tank, you have to be careful that no chemical gets into the tank as this is harmful to fishes and make sure the tank is cleaned as often as necessary.