How to Clean a Fish Tank

An aquarium is pretty and relaxing to look, only if it’s clean. And unfortunately, no matter how many filters you have, your fish tank will get cloudy and dirty and need cleaning. 

There’s no point in tearing down dirty fish tanks because it only leaves you without bacterial colonies needed for eliminating animal waste. That’s why you need to know how to properly clean your fish tank and not break it down. 

However, some of you may wonder how you should get about it. And if you should remove the fishes or leave them in, and lots of other things. Read on to find out all your answers!

How to clean a fish tank?

Cleaning a fish tank isn’t so difficult, as long as you have the right supplies and equipment. Here are step-by-step instructions on how you should give your aquarium a thorough cleaning, starting from cleaning the inside glass to the outer glass.

1. How to clean the inner glass

You can start by cleaning the inside glass with an algae pad. Don’t use the algae pads you find at regular department stores because they contain chemical remnants. While these pads are safe to use for general cleaning, they are dangerous to fish. 

Instead, use algae pads you get at pet shops.

There are quite a few types to select from, ranging from long-handled to magnetic scrubbers. Don’t worry about stubborn residue. You can scrape them off using razor blades.

2. How to clean rocks and decorations

With the inner glass clean, the next step involves removing the rocks, decorations, and artificial plants covered with algae. Don’t make the mistake of using soap or detergents for cleaning purposes because a trace can harm your fish.

Instead, use an algae scrubber and warm water to remove all the algae and dirt.

And in case of stubborn algae, soak the items in a 10% bleach solution for about fifteen minutes. Then scrub away any remnant residue in water and air-dry to eliminate bleach. 

It’s better to rinse them with water with de-chlorinator or sodium thiosulfate to remove the chlorine. It’s if and when you know there is no chlorine, can you put them back into the aquarium. 

While it’s okay to bleach live plants to remove the algae, stem plants do not tolerate bleaching. Soak them in a 5% bleach solution for about 2-3 minutes and rinse thoroughly. 

Leave all the rocks, plants, and decorations outside as you vacuum clean the gravel. It prevents the gravel debris from settling on them.

Always use a designated bucket for aquarium cleaning purposes. Buckets with soap remnants may end up introducing unwanted chemicals to your aquarium. 

3. How to clean gravel 

Now about cleaning aquarium gravel, it’s best done with a water siphon. It can effectively vacuum away any debris. Siphons work by stirring up and removing debris from the gravel. 

Do vacuum and remove all debris on the gravel. There is a chance of the vacuum removing some water, which should be replaced with dechlorinated water. The replaced water should be as hot as your aquarium water. 

4. How to clean the exterior glass and fixture

Now that the inner side of the tank is clean, it’s time to start with the outside.

Don’t use regular glass cleaners to clean the exteriors. They contain ammonia that’s dangerous to your fish. Even standard lime cleaners are not safe on your fish.

What’s safe is vinegar or an aquarium-use cleaner. And once done, use a clean and damp cloth to clean the surfaces.  

5. What about cleaning filters?

You can now restore everything to your clean fish tank. However, it’s better to wait for a few weeks to clean the filter. 

You may wonder why you need to wait. 

Well, it’s because your cleaning has already shook any beneficial bacteria there was on the rocks, plants, and gravel. While this is inevitable while cleaning, the good news is that there’s still some beneficial bacterial in the filter.

So, in short, you’ve not entirely disturbed the aquarium because you still have your ‘unclean’ filters.

If you have done a filter change, then there’s the risk of triggering an ammonia spike. It’s because of the absence of beneficial bacteria to eliminate toxins. 

6. How to clean filters?

Now about cleaning filters, carbon, ammonia absorbers, or ion-exchange resins that are more than three weeks old need replacement. Its’ absorbing qualities exhaust in a few weeks and ineffective as a filter. 

You don’t need to replace filter media like ceramic rings and sponges.

They act as mechanical filters and do not absorb toxins. So it’s enough to gently rinse them and affix to the filter. 

It helps if the water you use for cleaning is as hot as the aquarium water, and if you quickly affix the media to the filter. This prevents the complete loss of beneficial bacteria. 

Don’t forget to give the filter a thorough cleaning of all its parts. A filter brush proves helpful at removing any accumulated sludge in the small parts. 

Can you use vinegar to clean your fish tank?

In short, yes, you can use vinegar to clean your fish tank. 

However, there are a few things you should know before using it for cleaning purposes or to adjust water pH levels.  

Of the lot, distilled white vinegar is the best for fish aquarium use because other types like apple cider and wine vinegar contain organic materials. They can prove dangerous to aquarium fish. 

Vinegar cleaning

First, create a solution by mixing one cup of vinegar in one-gallon water. Use it to remove mineral deposits on the parts above the water. Don’t do this by spraying the solution but by pouring a little of it to a rag and then gently rubbing the affected regions.

This and the water carbohydrates neutralize the minimal vinegar entering the aquarium water so that it’s safe for the fish. 

Reducing water pH levels

Adding vinegar to aquarium water helps because the acetic acid combines with water oxygen to convert to carbon dioxide, water, and bicarbonate. The increased carbon dioxide levels reduce the aquarium water’s pH level.

Experts suggest that a diluted solution of 1ml of commercial white vinegar per gallon of water helps reduce the water’s pH levels by 0.3 points. 

However, do remember that excessive carbon dioxide, and reduced oxygen levels in the water, can damage the fish.

First measure the water’s alkalinity and pH a few hours before and after adding vinegar if you are using vinegar to lower the system’s pH levels. It’s also better to start with small amounts and gives the system time to equalize before adding more. 

Do you take the fish out of the tank before cleaning?

You don’t have to take out your fish every time you clean your fish tank. It’s usually more than enough to do it once in a while. 

How to remove fish from an aquarium for a cleaning

You need to take out your fish from the tank while cleaning it every once in a while. Regularly taking them out of their habitat can get stressful for them, and even make them sick. 

How to relocate fish while cleaning

  • You will have to transfer the fish from their tank into a separate container. You may also have to move your fish if you have a small tank, and you can’t clean it without injuring them. 
  • The container may not have to be as large as your tank.
  • However, it should be broad and deep enough to hold all of your fish and still have room for them to swim around without accidentally jumping out of it. Sometimes a large mug will suffice, especially if you just have one or two fish. 
  • Don’t forget to rinse the container with cool water to remove dust and debris before transferring your fish. As for the fish tank, do not use any chemical cleaners to clean the container for your fish. There is the risk of some remnants remaining even after rinsing, which is harmful to your fish.
  • The container should be filled partway with the aquarium water using a clean glass or measuring cup.
  • If you wonder why you should fill the container with aquarium and not tap water, well, it will keep your fish from going into shock. It’s the same water, so there’s no need for your fish to get accustomed to any new water temperature or pH balance. 
  • Remember, both salt and freshwater fish are sensitive to water temperature and chemical levels. So do not, at any cost, put fish directly into tap water. 
  • Always first wash your hands before reaching into the tank. It’s better if you wear gloves to protect your fish from any possible bacteria in your hands.
  • Always remove the aquarium decorations first before removing fish. It’s even better to clean the decorations before removing the fish. This way the fish stays out of their habitat for a shorter time. 
  • Use a net to gently scoop and transfer one fish at a time into the container. Do cover the top of the loss with your hand so that they don’t wiggle out. You just have to submerge the net into the container, and the fish will swim out on their own. 
  • Do not drop fish into the container water from a height, or flip them out of the net. You may need to use two nets, and have patience if you have fast-swimming fish because they may be challenging to catch. 

How often should I clean my aquarium?

Regularly maintained tanks should require extensive cleaning only once in six months. However, tanks without water pumps, filters, and maintenance equipment have to be manually cleaned more often than larger aquariums.

 It depends on how many fish you have and how messy they are.

On average, you may have to clean your tank every fortnight. However, you may have to clean it more often if your aquarium is smelly or you have an algae problem.

However, be aware that these are also signs of a problem that can’t be ignored. That’s why it’s better to test your water quality every time you clean the aquarium. 

How to remove and also prevent white residue on the fish tank glass

Do you notice some white water residue on the glass tank top? If yes, it’s because of hard water evaporation. Yes, while hard water is better for some fish, it’s not suitable for the transparent glass of the aquarium. This residue is nothing but limescale, which is a lime build-up. 

Mineral-rich hard water leaves residual heavier elements after evaporating, as a streaky line of white residue. It’s not harmful to your fish or aquarium but makes the aquarium harder and unpleasant to look. 

As usual, don’t use regular cleaning products but use something safe for removing lime build-up or plain white vinegar. 

You will, however, have to first shift your fish to a container to remove the lime deposits. Remove the water, plants and decorations after shifting the fish.

Now place the tank on a surface and pour sufficient vinegar to cover the streaked glass. Leave it on for about fifteen minutes and then scrub with a soft cloth.  

In case of stubborn patches, scrape it away with a razor blade and then rinse the tank thoroughly before refilling with water. 

Prevention is always better than cure, even in the lime build-up.

As evaporation is the main reason for the residue, check the tank’s water level every few days. The remaining water increases its density of minerals as the tank water evaporates.  

Distilled water is the best replacement for hard water because it’s pure. It’s anyway pure, and not hard water, that leaves the aquarium.

Do not make the mistake of replacing the water with water rich in minerals. It only leaves you with water dangerously concentrated with minerals. Distilled water helps neutralize and eliminate the risk. 

How to clean an empty fish tank

Old and used fish tanks tend to collect debris, grime, soil, and hard to remove stains on the glass. You will have to clean it using natural cleaning methods, without hard chemicals which only create a toxic environment for your future fish. 

Start by rinsing the aquarium with warm water and a moderate pressure hose to remove the surface dirt and grime. Then drain the water and wipe the glass with paper towels to remove loose dirt. 

You are now left with only hard stains to be removed by running an algae scraper over the glass. Dip a kitchen sponge in water and follow the scraper, scrubbing with firm pressure until the stains break. Use paper towels to remove all loose grimes during the scrubbing process. 

Once you clean the tank, it’s time to sanitize it. Do this by pouring a cap of bleach on paper, and wiping over the interior aquarium glass to kill any living organisms.

Don’t sanitize the exterior glass walls. Once done, set the tank in the sun for a few hours so that the bleach breaks down and loses potency. The sun exposure ensures there’s no worry about the bleach affecting the water or fish. 

You now have to get the tank ready for the fish. Do this by spraying the glass with nontoxic aquarium glass cleaner and then wiping it clean with a paper towel. Your glass is now clear and ready for your gravel, water, and fish habitat.

Ongoing aquarium maintenance

Once you have cleaned your aquarium, it’s better to clean it so that it doesn’t need a significant spring cleaning regularly. The glass will need a weekly cleaning while the gravel needs vacuuming every time you make a change. 

Make it a habit to clean any decorations, rocks, or plants as soon as you notice debris or algae. The filters need monthly cleaning by replacing or rinsing the media. It’s also worth soaking fishnets in a disinfectant solution so that they remain clean and soft. 


1. What should I do when fish gets caught in the fishnet?

You can put the net back into the water and use your hands to set it free. However, avoid touching the fish in the process. 

2. Should I use the same water while returning the fish to the aquarium?

No, always use fresh water, and make sure you have a water filter to filter the water regularly. 

Affiliate Notice is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to