How Often Should You Clean Your Fish Tank? A Complete Guide

There’s a common mistake many young or newbie aquarists make when they decide they’re going to keep fish.
For some reason, lots of beginner aquarists seem to think that fish do not require hardly any maintenance and don’t need much looking after.

clean fish tank

In fact, nothing could be further from the truth and knowing how to clean a fish tank is a fundamental skill for any aquarist.

Sure, you don’t have to walk your fish twice a day, or get them vaccinated, or trim their fur or clip their nails. They don’t need to chase a ball for exercise (unless it’s a moss ball) or have a toy mouse thrown around to play with.

But you absolutely DO need to take care of your fish properly, and that includes understanding how to clean a fish tank, how often you should clean it and the equipment inside it.

So how to clean a fish tank? How often should you clean your aquarium? How often should you clean your aquarium filter? How often should you change the water in your fish tank? Should you remove your fish when you’re cleaning your aquarium?

In this article we’ll cover everything you need to know in order to keep your fish tank clean and make sure your fishy friends are happy and healthy.
So, keep reading to know more on how to clean a fish tank.

How to clean a fish tank in theory is quite simple but needs to be done on regular basis.
Dirt is like tinea – it spreads really quickly if you don’t take care of it.
If you do a little bit every day, it’s manageable. You can stay on top of things and avoid having to do a massive horrible clean because everything has gotten disgusting.
And your fish will thank you for this, because after all it’s their home that you’re allowing to get dirty – and it’s not fair on them. Your fish rely on you to look after them!

So the best way to stay on top of cleaning your fish tank is to look after it properly in the first place.
There aren’t any super strict guidelines about how often you should clean your tank.
It depends on things like how many gallons of water it holds, how many fish you’re keeping (and what type), and whether you have live plants or animals that will help keep it clean.

Cleaning schedules will also differ depending on whether you have a coldwater tank or a heated tropical tank, whether it’s freshwater or saltwater, what kind of filter or filtration substance you’re using, and the sort of lighting that you’re running.
As you can see, that’s a lot of different factors to think about!

Water Change: How much water for a partial water change?

Whether you’re keeping coldwater or tropical fish, in freshwater or saltwater, partial water changes are essential for fish health.

Guidelines vary when it comes to the amount of water that you should change each time. Some aquarists advise a 15% water change once a week, while others suggest 25% or even 30%.
The best amount for your tank will depend on your tank size and how many fish you’re keeping in it, along with what kind of filtration options you’re using.

You can use different online calculators to help you figure out how much water you need to change, and how often.

As a rule, a 10-15% water change is a good place to start. As fish are sensitive creatures, you don’t want to change too much water at once.
It can stress your fish, and also potentially remove too much of the beneficial bacteria that live in the water.

How to clean a fish tank

Before you start a water change, it’s important to make sure your hands are clean and dry.
You want to make sure you’ve removed all traces of soap or detergent, as there are chemicals in these products that can be very harmful to your pets.

Begin by checking your tank for algae.
You can scrape this off before you change the water, by using a commercially available algae scraper or floss.
You can also use an algae scouring pad or one of the new magnetic glass cleaners.

To change the water, use a siphon tube to remove around 10-15% of the volume in your tank.
As you are removing the water with a siphon tube, use this to gently suction debris and algae out of the gravel as well.
Be very gentle as you’re doing this, you don’t want to frighten your fish with lots of vigorous activity!
Go slowly and give your pets time to adjust to what is happening.
To use a siphon tube, you don’t need to suck on one end to get the suction moving.
It’s much easier fill the hose with water by submerging it completely in your tank.

Once it’s full, put your thumb over one of the open ends and then move that end out of the tank and into your bucket. The pressure will cause the water to enter the bucket by itself – no sucking required.

Don’t throw this old tank water out straightaway.
You’ll use it to rinse or clean your filters and filter media, so that you are keeping the beneficial bacteria that have colonised those materials.

Never clean a filter under the tap!
You’ll kill off all the healthy critters that help to keep your tank clean and your fish in good health.

After you’ve vacuumed the gravel using the suction tube, you can add your new water to the tank. You should use a special bucket that you only use to add fresh fish water.
Make sure you never use this bucket for anything else, and never let soap or detergent get into the bucket.
Even the tiniest amount of residue can be unsafe for your fish.

It’s important that you don’t use water straight from the tap, as it can have chlorine and other additives in it that are dangerous for the health of your fish.
Leave it to sit in your special fish water bucket overnight to let the chlorine evaporate.
Or, you can treat it with a dechlorinator.

Once the water is ready to add, pour it into the tank slowly.
You should add it in a gentle, slow stream so that it mixes well with the original tank water.
Or, you can add it using the siphon method, but in reverse.

What tools do you need to clean your fish tank?

Here’s a list of basic items that you can consider using to keep your aquarium clean and fresh.
You’ll see we’ve linked some tools to products on Amazon that you can consider when you’re stocking up on your equipment.

Should you remove your fish when you’re doing a tank clean or water change?

Again, there are no hard and fast rules here. It will depend on the size of your tank and the kind of fish you have.

If you have a very large tank, you may find your fish will move away while you’re cleaning an area and won’t need to be removed specifically.

If you’re doing a small water change – say 10-15% – then you shouldn’t remove the fish, even in a small tank or bowl, as this sudden change can stress them out.

How often should you clean your aquarium filter?

There are three primary kinds of filters you might use in your fish tank – mechanical, chemical and biological.

  • Mechanical filters

    will need their sponge or foam pad cleaned around once a month – but make sure you don’t do it at the same time you do a partial water change. It’s a good idea to do it a week or two after, so that your fish don’t get two shocks at once. You should always clean the filter by swishing it around in water that you take out from your aquarium. Don’t clean it under the tap – we have already cover the reasons of this above. Just wash off the gunk with your hands and then replace the sponge or pad.

  • Chemical filters

    such as carbon filters need to be changed regularly, for example around every 3-4 weeks. It’s a good habit to get into doing this once a month along with your partial water change. You might need to do it more often if your aquarium water becomes cloudy very quickly.

Check our article for more detailed information about the filter types, different filter functions, media and cleaning schedules.

Cleaning your fish tank after a fish dies

It’s not a topic that anyone likes to talk about, but chances are that at some point you will experience a fish dying.
After this happens you’ll need to take steps quickly to make sure infection and bad bacteria don’t pollute your tank.
The first thing you should do is remove the dead fish as soon as you notice it.

Once a fish dies it will begin to decompose immediately, which means waste and noxious chemicals will enter the water.

Once the fish has been removed, test your water. Bad water quality is often one of the biggest contributors to fish death.
High ammonia and nitrate levels can kill fish quickly, especially if you have a small tank where pollution levels can spike suddenly if you aren’t staying on top of your regular cleaning and maintenance routine.

If the results indicate high ammonia or nitrate levels, you should do a partial water change to help improve the water quality for your remaining pets.

But what about if the water results come back in the normal range?
Now it’s time to see if there’s anything obvious you can notice from the dead fish.
What might have caused it to die? Is it bloated? Is there fungus or slime trailing from its body?
Finding out what killed your fish will help you take any necessary corrective action.
It could be a fungus, a parasite or an infection.
In this situation, seek advice from your local fish expert or pet store on the best way to treat the tank.

A good cleaning routine for your tank

Here are some general guidelines to consider when you’re thinking about how often you need to clean your tank.


If you’re cleaning your tank every day then can we kindly suggest that you might be being a bit obsessive about it and you should probably (read, definitely) relax a bit.
You don’t want to get rid of all the beneficial bacteria inside your aquarium.
Aquariums are little mini eco-systems and they need a certain level of bacteria and dirt in balance so that they run effectively.

What you can do instead though, is make sure you’re having a careful look at your tank every day.

This will help you get familiar with the cycle of your tank, the health and behaviour of your fish, and the levels of gunk and harmful chemicals in the water.

Take a good look at your fish.

Do they all look healthy? Are they following their usual kind of behaviour, or doing something different or unusual? Are they trying to gulp for air? Do they look stressed, or sluggish? Is their colour healthy? Do their fins, tails and scales look clean and vibrant? Is there any slime or fungus hanging onto them?

What about the tank itself?
Can you see any algae starting to form on the aquarium walls, or on the driftwood or decorations you have in your tank? Are the plants a healthy green colour? Are there any brown spots or leaves? Are there any loose or rotted leaves floating at the top or lying on the bottom?

Get to know your fish and their habitat in this way, and it will help you to spot any potential problems more easily.
And that means you can take action quickly – for example, you might need to do a partial water change, even if it’s been less than a week since the last one.


How often should you clean a small aquarium?
If you’ve got a 5 or 10-gallon tank then the answer is definitely at least once a week.
Remember, the water inside your aquarium is like the equivalent of the air to your fish.
Would you want to have to swim around in water that’s old, polluted with ammonia and other harmful substances, and full of floating bits of rotten food and fish waste?
It sounds pretty gross, doesn’t it?

You should do a partial water change and use your aquarium vacuum to clean your gravel.
Take care of any algae that’s formed around the walls or your decorations by using a sponge or a scraper to remove it.
It’s also a good idea to get into the habit of counting your fish once a week, especially if you’re running schools of little ones.

A tiny tetra or other small type of fish can die and drift to the bottom unnoticed, causing the ammonia and nitrate levels in your tank to spike quickly.

If you’re running a bigger aquarium, say of around 15 gallons and up, then you should still consider a partial water change at least once a week in order to keep the tank fresh and clean.
In really big and well established tanks though, you might be able to change the water once every 10 days or two weeks instead.


Testing your aquarium water for ammonia, nitrate levels and the pH reading is an excellent way to monitor the health of your tank environment.

You should test your tank water at least once a month.
Other cleaning tasks that should be done on a monthly basis are filter media or filter cartridges, and air stones for any clogging or build up.

It’s a good idea to note these readings in a special notebook or in a notes file on your phone, so that you have a reliable record from month to month and you can track any changes quickly and easily.

If you notice the levels starting to shift, you should test the water more frequently.
And if your fish are starting to look stressed or unhealthy, you shouldn’t wait out the month before testing again.
Is the water getting cloudy or turning a strange colour?
It’s time to test.

For filter media and cartridges, rinse these using the water that you take out from the tank during the water change.
Again, don’t use water from the tap!
You want to support the bacterial colonies, so gently swish the cartridges or media in this tank water instead.

For air stones, you can clean these either by boiling them in fresh, clean water, or by simply replacing them entirely.

During the monthly clean you can also take the opportunity to replace any filter inserts, cartridges, carbon or floss.

Lastly, check the expiration dates on all the aquarium supplies you use.
It’s easy to lose track of how fresh the supplies are in their boxes and bottles, and you don’t want to be testing your aquarium water with a test kit that’s actually expired.
It could give a false reading and you might take action that isn’t necessary, and that could accidentally harm or kill the fish or plants inside your tank.


It’s a good idea to give all the equipment in and around your fish tank a solid clean at least once every six months.

Doing this will help you keep an eye on how all your equipment is functioning, so that you can repair or replace it if you need to.
It also gives you an opportunity to really clean everything properly.

Turn off and unplug all the equipment you have in your fish tank.
Inspect all your equipment carefully, and use the opportunity to get out any dust, dirt or debris that has snuck in there.

This includes tank hoods, filters, pumps and light fixtures.
Wipe down the hood and the pump housing before putting everything back together

Deep cleaning your fish tank

A deep clean refers to taking everything out of your tank and scrubbing it clean from top to bottom.
This includes removing fish, water, ornaments, plants – the lot.

A deep clean is a dramatic approach that you should only do under dire and special circumstances, such as if you have a disease outbreak in the tank that can’t be fixed by any other method of treatment.

Because a deep clean involves taking everything out of the tank, it is incredibly stressful for your fish.
It will also kill all the healthy bacteria in the tank and you’ll need to carefully establish those colonies again and cycle your aquarium properly before your tank will function effectively after the clean.


As you can see, there are a lot of merits to keeping on top of your aquarium cleaning routine.
Not only does regular aquarium maintenance help keep your fish healthy and thriving, it gives you the best chance of being top of any issues before they become real problems that might harm your pets.
Your fish will thank you for their fresh, clean water, and you’ll have a beautiful, sparkling tank to admire. What could be nicer?!
What do you think? What’s the best frequency for tank cleaning in your experience? What kind of water changes are you doing?
Tell us in the comments!

How often should you clean your fish tank and how? How often should you clean your aquarium filter? How often should you change the water in your fish tank? Should you remove your fish when you’re cleaning your aquarium? These questions and more answered in this guide to cleaning a fish tank.