No matter what size of a fish tank you have, it will get dirty. No matter the tank’s filter type, it needs help to work. To do this, you need to clean your fish tank regularly. Keep reading to learn more about how to clean a freshwater tank.

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How Often Should You Clean Your Freshwater Tank?

You don’t need to clean your fish tank daily. However, you should check on your fish to ensure they behave normally. It’s good to check the overall tank daily because anything can happen at any time.

Once a week is ideal for cleaning your freshwater tank. You might get away with doing fewer water changes if you have a larger setup. However, weekly is a good idea if you have a smaller tank.

Partial water changes are enough every week, but you should also check on the filter once a month. If cartridges need a quick clean, monthly is a good time to do that.

Also, if you don’t test your water once a week, that should be done monthly. 

Finally, once every six months, you should thoroughly clean your fish tank. Deep cleaning includes taking out the decor, rinsing them off, changing the filter, and checking to ensure all the equipment (the heater and lights) is working correctly.

hand cleaning algae from a fish tank

Why So Much Work For A Fish Tank?

Much like your other pets, fish are living creatures. Proper care includes regular cleaning. Cleaning your fish tank regularly makes it look aesthetically pleasing to you and ensures the fish health and well-being, overall caring for freshwater fish.

However, it’s good to remember where certain fish species come from. In the wild, some fish species are used to dirtier water with algae. Betta fish, for example, originate in swamps.

So, it’s not the worst if the tank water is slightly dirty with some algae. You’ll still want to keep doing water changes to ensure the water doesn’t have harmful chemicals. But some of the dirtiness on the decor might make your fish feel more at home. 

Step-By-Step Guide On How To Clean A Freshwater Fish Tank

Once you know your aquarium’s needs and how to help your fish community thrive, cleaning your tank is relatively easy. Larger tanks require more work, but you may be able to get away with fewer water changes. Regardless, cleaning a tank is universal among all freshwater tanks.

Step 1. Gather Your Cleaning Supplies

You’ll want to ensure your cleaning equipment is ready. The supplies you’ll need are as follows:

  • Algae pad (or algae scraper)
  • A bucket (that holds 2 to 5 gallons)
  • Gravel vacuum (a water siphon)
  • Water conditioner (dechlorinator)
  • Water quality testing kit
  • Thermometer
  • Towels
  • Glass cleaner
  • Scissors (if needed, for live aquarium plants)
  • Step stool (if needed)

Once you have all of your equipment, ensure it’s set up. For example, lay one towel in front of your aquarium to catch any potential spills. You can have a second towel on hand to dry your hands and other supplies in the middle of cleaning.

If you’re short like me, a step stool is ideal beside the tank. You’ll be able to reach the bottom of the aquarium easily, depending on how deep the tank is and how high the aquarium stand is.

Everything else will be used to clean the tank and to ensure the water levels are good before and after cleaning.

fish tank with fish, gravel, plants, and rocks

Step 2. Unplug Tank Equipment

Before you begin, you’ll need to unplug your tank’s heater and filter. These won’t work well in dry air and can become damaged.

If you’re planning on draining enough water that won’t cover the heater or filter, it’s best to unplug them temporarily.

You can keep the lights on if the lights aren’t connected to the filter. They won’t be affected as much, and you’ll be able to see better when cleaning.

Step 3. Wash Your Hands

Before you do anything else, wash your hands up to your elbows. If you have a deep tank, then chances are, your whole arm will be in the water.

Washing your hands will ensure your skin is clean enough and won’t transfer harmful germs or bacteria into the tank water.

Now you can finally begin cleaning the tank!

Step 4. Clean The Inside Of The Tank Glass

Algae build up on the glass walls inside the tank. You might notice this every day when looking at the tank because there will be brown-green spots on the glass.

Before you siphon out any water, take your algae scraper and remove the algae on the glass.

You don’t need to remove it all. Some algae are good; if you have snails in your tank, they’ll eat the algae and clean it for you. So, if you’re having a hard time reaching algae on the backside of the glass or in a corner, it’s okay to leave it as long as you get most of the rest.

We clean the inside of the tank’s glass before siphoning any water out because the algae will scrape off the glass and float in the water. Then, the loose algae will get sucked out when you siphon the water.

algae clinging to the inside of a fish tank

Step 5. Prune Live Plants

If you have live plants decorating your aquarium, it is time to propagate some of them. You can take some scissors and cut them back if they’re overgrown.

Also, if you have live plants floating at the surface, you’ll want to remove at least 30% of them. The surface should not be completely covered so that light and oxygen can get into the water for other live plants and fish.

Step 6. Clean Aquarium Decorations And Rocks

As mentioned earlier, you don’t need to clean the decorations at every water change. You’ll only need to do it once every six months or as needed if things are looking too dirty.

However, if this particular water change calls for you to clean the decor, now is the time to do so.

You can clean the decor in a few ways, depending on how dirty they are. For instance, if they’re not as dirty, you can take a small algae scraper (or an unused spare toothbrush) to remove the algae before changing the water.

Alternatively, you can take the decor out of the tank, scrap the algae off in the sink and rinse it with water. You can use dirty tank water to rinse it, too, as you siphon out the water. To keep the decorations clean, it’s a good idea to keep them out of the tank until after your water change.

You can clean the decor with 50/50 water and vinegar if it is stained. Be sure to rinse it well before placing it back into the tank.

Step 7. Siphon The Water And Clean The Substrate

This step is the most important. Fish waste and excess fish food can get buried under the substrate. Even if you have a catfish or another bottom feeder, debris will still escape underneath.

You’ll need your gravel vacuum and bucket. Water will be siphoned out of the tank as you clean the substrate.

Try to clean at least 50% to 75% of the substrate during each cleaning. This will ensure the tank stays as clean as possible while keeping the nitrate levels low.

When doing this, the water levels will undoubtedly go down. As a reminder, ensure the heater and filter are unplugged in case the water levels get too low.

fish in a tank surrounded by live plants

How To Clean Different Aquarium Substrates

Gravel is the most accessible type of substrate to clean. With your gravel vacuum, you can push the tube into the gravel, swirling it around, picking up any debris underneath, and sucking it up through the tube.

Connect the other end of the siphon to your bucket. Once the bucket is full, empty it down the drain or outside. Then repeat the process until you’ve covered most or all of the ground.

If you have backed clay substrate, then cleaning is similar to cleaning the gravel. 

On the other hand, if you have sand or aquarium soil as your substrate, cleaning will be trickier. You’ll need to use a siphon hose, but be mindful that the soil and sand can easily get sucked through the tube and get cleaned out of the tank along with the debris.

The easiest way to ensure this doesn’t happen is to clean the surface of the substrate. Go slowly so that not as much of the substrate gets siphoned.

You can always add more substrate after the cleaning if needed.

Step 8. Clean The Filter Media

You won’t need to clean the filter media when changing the water. However, if this particular cleaning calls for it, then now is the time to do so.

Before you dump out your final bucket of dirty tank water, take the filter cartridge and rinse it in the dirty water.

You don’t want to rinse it in tap water, or else you’ll get rid of the beneficial bacteria needed to filter throughout the tank.

Of course, there are many filters so cleaning will vary.

For example, if you have a sponge filter, you’ll need to squeeze the sponge out of the bucket filled with dirty water before putting it back into the tank.

empty fish tank with brown gravel or sand, live plants, and rocks

Step 9. Refill The Aquarium Water

Now it’s time to add water to the aquarium. Before you do so, you can place your aquarium decorations, rocks, and artificial plants back into the tank.

Then, fill your bucket with lukewarm tap water and pour it into the tank.

A thermometer is a great idea to see how warm the tap water is before placing it into the tank. Remember, your heater is unplugged right now. Adding cold or hot water may shock your fish.

You’ll want to add tap water within the temperature range your fish need to thrive. That way, when you do turn the heater back on, it won’t need to do much to get the water temperature back to normal.

Tap water has harmful metals and chemicals that aren’t safe for your fish community. So, when adding water, use your water conditioner.

Seachem Prime and Stress Guard or API Quick Start and Stress Coat are excellent options. You can add the conditioner to the water in the bucket before adding the water to the tank. Or you can add the conditioner directly to the aquarium after refilling it and letting it filter through.

When adding the water to your tank, do so carefully and slowly. Otherwise, decorations might flip over from the water pressure, and gravel may kick up.

Step 10. Turn The Equipment Back On

Once your tank is refilled, it’s time to plug everything else back in. Turn the filter and the heater back on. After a few hours, the temperature will return to where it should be, and the filter will work hard to keep the water clean again.

Step 11. Clean The Outside Of The Tank And Lid

This step isn’t necessary, but like the windows in your house, you’d like to see through the clear glass to view your fish, right?

A little Windex on the outside of the tank’s glass will do fine to clean it as long as it does not get inside the tank.

To get a streak-free clean, you can use a squeegee with 50/50 water and vinegar on the outside of the tank. This solution will also work well on the tank’s lid.

If the cover isn’t as dirty, rinse it with water and wipe it down with a towel.

hand cleaning the inside of a fish tank with a sponge

Step 12. Clean Up And Wash Your Hands

When the tank is all set, it’s time for you to clean up all your supplies. The bucket, siphon, and everything else used for the aquarium should be stored specifically for your fish tank.

If your aquarium is on a stand, then under the stand should be a great place to store these items.

Towels should go in the laundry, even if they’re not dirty.

Finally, when everything is put away, wash your hands again. If you went into the tank up to your elbows, wash your arms, too.

An Extra Step: Test The Water

You should test the water at least once monthly to ensure that the ammonia, nitrite, nitrate, and pH levels are normal.

However, 24 hours after a water change, it’s a good idea to test the water. By doing so, you can be sure that the water change was successful and that the water conditioner filtered through well.

Alternatively, you can test the water right before changing the tank. You can make the necessary adjustments if any levels are abnormal during your water change.

We use the API water testing kit that works well.

Question Corner: FAQs About How To Clean A Freshwater Tank

The process is relatively simple, even though it takes some time. A larger tank will take longer to clean than a small one. But if you have more questions, read through the frequently asked questions answered below.

group of blue neon tetra fish in a fish tank surrounded by plants and rocks

Should I Remove The Fish To Clean The Tank?

No, this isn’t necessary. It creates more work for you and will stress the fish out. Also, if you have a large community, that would be a lot to take out of the tank. Fish are sturdier than you think and can handle water changes well.

What Does Cleaning The Tank Accomplish?

Not only will you make your tank pretty to look at, but you’ll create a healthy environment for your aquatic community. You’ll also reduce harmful compounds, remove decomposing waste materials and debris, and add essential elements and minerals into the water. 

Should You Clean The Tank If A Fish Dies?

If you find a fish dead in your aquarium, remove it immediately. Then, try to determine the cause of death. Maybe your fish was simply older, and it was their time. If that’s the case, you shouldn’t have to worry. If the water levels are off or other fish seem ill, it’s best to change the water again. 

Cleaning Your Freshwater Aquarium Is Important

Regular cleaning is essential to maintain a healthy environment and keep fish thriving. While it’s somewhat of a process, it’s easy to do once you start getting the hang of it. Not only will your tank look pristine, but your fish will be happy, too.

fish tank with plants and gravel with text centered reading: 13-Step Guide On How To Clean A Freshwater Tank |
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