New aquarists may be daunted by the task of cleaning their aquarium, however, it is not as difficult as they may think! In fact, most new aquarists are prone to over-clean their aquarium. To learn how to clean an aquarium properly, follow the steps and tips in this article.

How to clean a fish tank

Tips For How to Clean a Fish Tank

The first tip to help keep your fish tank clean is to properly set up the aquarium. You can learn more about that over on our fish tank set up guide. After your tank is set up properly and before you begin cleaning your tank, read the following tips to ensure that you clean your aquarium properly:

Avoid Contamination

It is very important to avoid contaminating your aquarium with germs from an aquarium that has sick fish, or from chemicals you use around your home, to include simple hand soap.

Before you put your hands into your aquarium, consider what you last did. If you recently had your hands in a fish tank with visibly sick fish, washed your hands, cleaned with harsh chemicals, or applied lotion, use disposable gloves to protect your fish.

Reduce Stress

Fish are highly susceptible to stress and the aquarium being cleaned can be a stressful event for them. Your goal is to clean efficiently, returning the tank to normal conditions as soon as possible, to minimize your fish’s stress. Only begin cleaning when you know you have sufficient time to do so properly. You should not remove your fish while you clean; it is not necessary and netting them is a stressful event that scratches their slime coat, making them susceptible to illness.

Be Mindful Of Appliances

It is very important to unplug your aquarium filter and heater before siphoning water out. Running a filter dry will damage it. A heater needs to be unplugged for approximately 15 minutes before water can be drained from around it, or you risk the heater shattering.

Do Not Over Clean

If you over clean an aquarium, you will remove the beneficial bacteria that your fish need to be healthy. On a weekly basis, you should change 25% of the aquarium water, and on a monthly basis, change the aquarium filter cartridge.

You should not do a 100% water change very often; that is really only appropriate when a fish is sick and you are attempting to treat the fish’s illness.

Watch For Babies

If your fish are happy, they will probably breed. Baby fish can be the size of a grain of rice, so as you siphon, watch carefully to avoid accidentally siphoning a baby fish out of the aquarium.

If you do not want your fish population to grow, leaving a baby fish to swim around the aquarium will cause natural selection to take place, as other adult fish will eat it.

If you want your baby fish to survive and thrive, purchase a net breeder for them to live in. When they are too large to fit in the adult fish’s mouths, they may rejoin the aquarium.

Prevention Is Key!

The best way to keep your aquarium clean is to prevent it from getting dirty and the best way to keep your fish healthy is to maintain good water quality from the start.

Water quality and fish health are impacted negatively by: overfeeding fish; failing to promptly remove excess food and deceased inhabitants; not performing weekly water changes; not changing the filter cartridge monthly; and not scrubbing algae off the glass.

Know that is it much more simple to maintain a healthy aquarium than it is to rehab an unhealthy one. Your local fish store should be able to assist you with this.

Cleaning an aquarium


Required Supplies For Aquarium Cleaning

Use this list as you shop for aquarium cleaning supplies to ensure that you purchase everything that you need:

  • Siphon (aka Gravel Vacuum).
  • Water Conditioner.
  • Beneficial Bacteria.
  • Aquarium Salt. (Yes, even for freshwater aquariums!)
  • A bucket for dirty water.
  • A jug for clean water.
  • Paper Towels.
  • Disposable Gloves.

It is very important that these items be dedicated to your aquarium. They should not be used for anything else, as if the supplies come into contact with cleaning chemicals or germs from an unhealthy aquarium, the fish living in your aquarium risk becoming sick and dying.

How To Clean An Aquarium In 6 Steps

Step 1: Assess and Unplug

Begin by unplugging your aquarium’s heater and filter.

Turn the light on so you can get a good look at the aquarium. Search for baby fish that might need to be caught, note where the most visible detritus (decomposed matter) is that will need to be removed.

Check if any of your fish appear to be unhealthy. If any of the fish look sick, research treatment before cleaning the aquarium as usual.

You will need to wait for the heater to have been unplugged for 15 minutes before you begin siphoning out the water. Use this time to test the water levels and to fill your clean water jug.

Step 2: Begin Siphoning

Put on gloves, and bring the paper towels, dirty water bucket, and siphon to the aquarium. The paper towels are helpful to have ready in the event that you accidentally spill water.

If you have never used a siphon before, here is a helpful video on how to use the siphon.

Place the bucket beside the aquarium, with the hose end of the siphon in the bucket and the siphon itself in the aquarium. If you are nervous about accidentally pulling the hose out of the bucket, zip tie the hose to the bucket handle to keep it inside.

Initiate the siphon, and vacuum as much of the gravel as possible until you have removed 25% of the aquarium water. If you have removed 25% of the water and there is still visible detritus, remove the waste efficiently to avoid removing too much water.

When the bucket is full, if you have flowers, use the dirty water from the aquarium to water your plants. This is an efficient use of water, and it offers fertilizer for your flowers. Otherwise, pour the dirty water into a toilet to dispose of it.

Step 3: Perform Necessary Maintenance Tasks*

*This step is to be performed once per month.

Once per month, the filter cartridge must be changed and decorations should be cleaned. Remove decorations and scrub them with your hands or an unused toothbrush under hot water to remove algae or other debris; never use soap or other cleaning agents.

Step 4: Replace Water

Begin refilling the aquarium with your clean water jug. Always add water conditioner before pouring the water into the aquarium. The water conditioner works instantly; it will be ready immediately.

Try to pour the water onto an ornament to avoid stirring up any remaining detritus in the gravel you may have missed. Do not pour the water directly onto a fish, as this may cause injury.

Extreme temperature changes cause stress to fish. Accordingly, avoid refilling an aquarium with very hot or icy cold water; room temperature is best. As soon as the heater is fully submerged, plug it back in so that the water will begin returning to the fish’s required temperature.

When the aquarium is almost completely full, save some water to pour into the filter to get it started. Plug the filter in, then pour water into it. You may hear it struggle to get started for a moment, but as long as you have put water in, there will be no problem. Never allow the filter to run dry.

Step 5: Add Beneficial Bacteria And Aquarium Salt

How to clean an aquarium

When the aquarium is back up and running, add aquarium salt and beneficial bacteria to help keep fish healthy and happy.

Aquarium salt is a general health aid, and beneficial bacteria helps keep the water levels you test in healthy ranges. Every time you clean an aquarium, you remove beneficial bacteria, which makes replacing the bacteria and avoiding over cleaning important.

Step 6: Clean Up

Take the paper towels and wipe up any excess water. Store the cleaning supplies in your aquarium stand, or anywhere that they will not be exposed to chemicals or other contaminants.

Never wash your siphon or any of your aquarium cleaning supplies with soap or other chemicals. If you think they look dirty, wash them by scrubbing them in hot water with paper towels.


Cleaning an aquarium is not a complicated process. Remember that your goal is to maintain a reasonably clean place for your fish to live. There is a balance between over cleaning and under cleaning that must be managed; do not do a 100% water change and scour every surface until the aquarium looks like no one has lived in it. Simply remove visible detritus, change approximately 25% of the water, test the water levels, and replace beneficial bacteria weekly.

Save it For Later

How to Clean a Fish Tank #pupnfriends