How to Clean an Aquarium or Fish Tank

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how to clean a fish tank

Table of Contents

How We Compiled the Ultimate Guide to Cleaning Fish Tanks

Expert Recommendations

Product Testing

Team Experience

Introduction – How to clean a fish tank

Knowing how to clean a fish tank is important if you want to keep your pet fish healthy. A clean tank improves the welfare and happiness of the fish and helps to keep the filtration system up and running.

A common mistake that many new pet fish owners make is to think that fish require little to no maintenance. Nothing could be further from the truth. Knowing how and when to clean your fish tank is an essential part of being a great pet owner. 

Sure, fish don’t require vaccination or a walk to the park but they definitely need you to keep an eye on their environment. So how do you clean a fish tank? How often should you do it? Can you or should you remove the fish while you clean the tank? And how often should you change the water?

In this article, the Cleaning King team will answer all these questions and more. We’ll cover everything you need to know about cleaning your fish tank to make sure that your pet fish stay healthy. 

We’ll start with a brief discussion about the most common types of fish tanks you’ll come across. We have also included a buyer’s guide at the end of the article to help you understand the cleaning factors you should consider when buying a fish tank.

how to clean algae from fish tank

Types of Aquariums

Our planet has thousands of different fish species in the world, and they survive in different environments. There are four main types of aquariums that cater to a variety of fish. These are:

Coldwater Aquariums

A cold water aquarium does not require you to heat the water. An aerator that keeps it at room temperature regulates the water temperature. A cold water aquarium can be used for freshwater or marine fish. This is a good aquarium for beginners or young children because it is relatively easy to maintain. 

Freshwater Aquariums

Freshwater tropical aquariums are perfect for fish that live in lakes and rivers. Although they are very easy to maintain, there are a few things that you should take into consideration. 

If you are a beginner, you must know that freshwater aquariums need to maintain a slightly higher temperature than cold water aquariums. This means that water temperatures have to be monitored carefully. 

You’ll also need to put effort into things like balancing the PH levels of the water. A freshwater tropical aquarium is a wonderful place to start keeping fish. It generally requires less maintenance and won’t cost much to operate. 

Saltwater Aquariums

Saltwater or Marine aquariums cater to fish that you will find in the ocean. These types of fish tanks require more effort on your part to maintain them. Marine fish are very fragile and cannot handle extreme changes to their habitat. 

This makes it very important to know how to clean your fish tank properly. Also, keep in mind that saltwater aquariums are more expensive to maintain than other fish tanks.

Brackish Aquariums

These types of fish tanks are very rare and can be hard to navigate for new owners. They are more suited for people that have had experience with taking care of both saltwater and freshwater fish. Why? Because brackish aquariums are a mixture of salt and freshwater.

How often should you clean a fish tank?

The question of how often to clean a fish tank is very important. Keeping your fish tank clean is simple, however, it needs you to have a consistent schedule that you stick to. If you have the energy, the best way to tackle cleaning your fish tank is to do a bit of cleaning every day.   

This strategy is perfect if you want to avoid having to deep clean often which can damage the health of your fish. Fish tanks build up good bacterial colonies that have many benefits including eliminating waste. A deep clean will remove these good bacteria colonies. Only do it if your fish tank becomes extremely dirty or something big like an infection or invading fungus happens. 

There are no strict rules that govern how often you should clean your fish tank. In fact, the decision is based on many factors, such as

  • The type and size of the tank.
  • The type of fish you have.
  • How many fish you have.
  • The type of filter or filtration chemical you use.
  • Whether you have any lighting or UV sterilizer.
  • Whether you have any live plants or animals that clean the tank.

There are several factors that you should think about, but the general rule of thumb is to do it at least once a month.

Before you clean your fish tank

Consideration #1 – Should I remove the fish first?

A common question is whether you should remove your fish when cleaning the tank. Again there are no strict guidelines, it depends on the factors we’ve listed above in our ‘how often should you clean your fish tank’ section. 

A good guideline to follow, for example, is looking at the tank size. If your fish tank is large, the fish generally move away when you clean a section. They have plenty of room so there won’t be any need to remove them. If your tank is smaller, you might want to consider moving them. However, experts don’t recommend this if you are doing a small regular clean or water change as this change can stress out your fish.  

Consideration #2 – What equipment will I need?

As with anything you can do an OK job, or an amazing job! The equipment and process we are detailing here are for doing an amazing job. We would recommend following this process a few times before deciding that there are suitable shortcuts for your particular fish tank.

Equipment you’ll need:

Whether you want to know how to clean a small fish tank or a big one, the cleaning process will be easier if you stage it using the following steps: 

  • Start with cleaning inside the glass.
  • Move on to the decorations (plants, rock, etc).
  • Vacuum the gravel next.
  • Clean the outside of the glass and the fixtures.
  • Lastly, clean the filter. 

Aquarium Scraper

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Aquarium Scraper Product Review

This Pro Aquarium scraper is fitted with wide razor blades that make it easy to scrape any algae or residue off the glass. It doubles up as a gravel spatula when you use it with the protection cover. 

The soft and sharp blade is glass-friendly and won’t leave any scratches on your beautiful glass aquarium. It features a long 26-inch handle made from Aluminum Magnesium Alloy, and the head is manufactured using strong ABS plastic. This makes it lightweight and easy to use with a comfortable grip that can be manipulated into three different lengths.

Stand-out features include

  • Easy to use.
  • Suitable for small to large tanks. 
  • Durable, adjustable handle.
  • Glass friendly.

Flipper Glass Cleaner

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Flipper Aquarium Glass Cleaner Review

This magnetic aquarium glass cleaner by Flipper is one of the best algae scrapers on the market. With many great reviews, this patented dual-sided magnetic aquarium glass cleaner can flip from scrubber to non-scratch scraper automatically. It can do the job quicker than some algae scrapers in the market thanks to the magnetic technology.

Stand-out features include

  • It automatically flips from scrubber to non-scratch scraper without intervention.
  • Will not sink to the bottom even when magnets are disengaged. 
  • Does the job in half the time of normal scrapers.

Step 1: Cleaning the Inside Glass

Effectively learning how to clean aquarium glass is essential to keeping the tank in tip-top shape. Algae are the number contaminate in fish tanks so you should start there. How to clean algae from fish tanks is pretty simple.

Invest in a good algae pad or scraper to make your job easier. There are several varieties of algae scrapers available for purchase. They come with different features such as extendable handles or a magnetic scrubber.  

Ensure that you get the algae scraper from a trusted pet store and not a regular shop. This is because the scrapers sold in regular stores can be contaminated with detergents which are fatal for fish. If you’re buying online, ensure that you verify the origin of the product. 

How to scrape the algae off the glass

  1. Start by inspecting your fish tank for algae to identify whether you’ll have spots that might cause you trouble.  
  2. Always clean and dry your hands before you attempt to clean.
  3. Ensure that you are not spreading any detergent or chemicals that might kill or hurt the fish.
  4. Scrape off the algae with a scraper. We have reviewed two of our favourites.
  5. If you come across any stubborn algae or residue, use the razor to gently scrape it off.
how to clean betta fish tank

Step 2: Cleaning Decorations and Rocks

How to clean aquarium sand and plants

  1. Start by removing all the rocks, artificial plants, and accessories, especially if they show signs of significant algae growth or dirt.
  2. If the dirt proves to be stubborn, use a 10 percent bleach solution and soak the decorations and rocks for at least 15 minutes.
  3. Scrub any remaining dirt off, rinse well under running water and let them air-dry to remove any lingering bleach.
  4. Use a de-chlorinator as an extra precaution before you replace the decorations and rocks back in the aquarium. 
  5. Only return the decorations and rocks once you have vacuumed the gravel so that the dirt you’ve stirred up won’t land on them. 

If you have live plants, the cleaning process is exactly the same, just remember to be more careful because they are living things. Also, do not soak live plants in bleach for more than 5 minutes. 

Again, do not be tempted to use detergent or soap. It’s better to have a little residue of algae left than to get rid of it with detergents. Usually, an algae scraper with some warm water will do the trick.  

how to clean fish tank gravel

Step 3: How to clean fish tank gravel

Cleaning your fish tank gravel is the third step you should take. The process is fairly simple, especially with the use of a siphon. There are several types available but they all work the same way. The siphon stirs up the gravel to dislodge debris from the bottom of the tank without sucking in the gravel. 

  1. Use a siphon to vacuum through the gravel to remove all the dirt.
  2. Ensure that you vacuum the entire bottom of the aquarium so that all the dirt is sucked away.
  3. Always remember to disconnect your heater when changing the water to avoid it being exposed to air as you drain the water.
  4. Add de-chlorinated water using your aquarium bucket to replace the water that you’ve sucked out. Always ensure that the water you pour in is the same temperature as the water in the aquarium.

The Cleaning King team reviewed two of the best siphon vacuums, and we’ve included them below.

Best Aquarium Gravel Cleaner

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Best Aquarium Gravel Cleaner

This awesome aquarium gravel cleaner features a 3-in-1 function. It is equipped with a duckbill suction inlet that sucks in dirt easily. It has a sand washing 3D filter basket net that prevents gravel or your pet fish from being sucked in. Lastly, it has built-in dual airbags that pump water quickly for more efficient water changing. It is made from durable material and it’s easy to use.

Stand-out features include

  • 3-in-1 function.
  • One switch easy-to-use button.
  • Durable and adjustable handle.
  • Can be used in many types of fish tanks.

Budget Aquarium Gravel Cleaner

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Budget Aquarium Gravel Cleaner

This Luigi manual siphon and gravel cleaner is great for regular water changes. Its simple design ensures that your cleaning sessions are not messy. It features a one-way valve that improves suction and can clear at least 30 liters in 5 minutes.


The user-friendly attachment can filter through the gravel with ease, sucking up all the debris from your tank. It also has an attached filter to keep your fish or other organisms safe from being sucked up. 


Stand-out features include

  • Value for money. Comes with several accessories.
  • User friendly.
  • Can pump water very quickly.
  • Manual control allows you to be in charge of how much water you pump out. 
how to clean fish tank exterior

Step 4: Cleaning the fish tank exterior

The fourth step is to clean the outside of the aquarium including any fixtures. This includes cleaning the hood, light, the top of the tank, and the exterior of the glass. 

Avoid using any detergent such as window cleaner or lime cleaners. These types of products contain ammonia or lime which is fatal to fish.

Always pick an aquarium-safe cleaner like ‘Safe & Easy’ and remember to thoroughly rinse all the areas you clean.

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how to clean aquarium filter

Step 5: Clean the Filter

The last step is to clean the fish tank filter. However, this process should not be completed on the same day as the cleaning. This is because even a small cleaning job disrupts the bacterial colonies in the fish tank.

The filter is usually the only place where the bacteria is left. So waiting at least two weeks before cleaning out the filter media will help to restore the natural ecosystem in the aquarium. Avoid cleaning the filter with tap water, this will kill off the bacteria.

The best item to use for this process is the filter brush. This will help you clean out any dirt that might hide in the small places that you can’t see. 

How often should you clean the aquarium filter?

Depending on the type of filter you have, you might need to replace it frequently. For example, if you have a chemical filter media that contains ion-exchange resins, carbon, or ammonia absorbers, you’ll have to change it after every three weeks.

Mechanical filters are fitted with a sponge or foam pad you can clean at least once a month. However, remember to schedule it at least two weeks after you’ve cleaned your tank.

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How to Clean a Betta Fish Tank

We have had many readers ask about cleaning Betta Fish Tanks in particular. The steps in this comprehensive guide also apply to Betta Fish Tanks, and will produce excellent results.

How to clean your fish tank after a fish dies 

Fish dying is an unfortunately common thing. They are very sensitive pets and any sudden changes to their ecosystem could prove deadly.

It is very important to act quickly once you notice that one of your fish has died. Once a fish dies, it begins to decompose quickly. Remove the dead fish to prevent infection and toxins polluting the tank and affecting the remaining fish.  

Proceed to test the water to ensure that the water quality has not caused the death of your fish. Water that has high ammonia or nitrate is one of the top causes of fish tank deaths. If the water has high ammonia or nitrate, you should change the water to improve the quality so that the remaining fish survive.  

If the water test comes back normal, then you’ll have to investigate other causes. Examine the dead fish. Check for signs of fungus, slime, or bloating which can point to various causes. You’ll have to embark on a process of elimination.

It’s very important for you to figure out what caused the fish to die. If you can’t, then enlist the help of a professional. They can help find out the cause of death so you can take the necessary steps to correct the issue.

Ongoing Maintenance for your aquarium

Repeat the above processes regularly, keeping in mind everything we’ve discussed in this guide. You must also pay special attention to how you change the water. There are certain factors you need to keep in mind.

First, know that changing the water partially when you clean the fish tank is essential to the well-being of the fish. Too much and you destroy the balanced ecosystem within the tank and this will stress the fish. There are different guidelines when it comes to the amount of water that you should replace when you clean your tank.

The amount of water you change depends on the size of your tank, your filtration system, and the number and type of fish you have. You can choose to change 15%, 25%, or 30% of the water once a week.  

If you are unsure, there are several online calculators you can use to find out how much water you need to change for your fish tank. If you are a beginner or if you have a small tank the recommended percentage is between 10-15% until you get the hang of it.  

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

How to clean an empty fish tank 

Knowing how to clean an empty fish tank for long-term storage is also important. Maybe you’ve taken a break from keeping fish as pets or you have bought a bigger tank and need to clean out the old one. Regardless of the reason, the following steps will help you keep your empty fish tank in good condition.  

Step 1: Clean the filter

Unplug the filter and soak it in a vinegar and water solution. Remove the carbon filter or sponge and throw them away because you’ll need to buy new ones when you use the tank again. Scrub the filter using a filter brush to dislodge any dirt, sludge, or algae. Allow it to air dry.  

Step 2: Remove the lighting

Prepare the lighting for storage by removing it from the tank. Store the lightbulbs in packing paper or wrap them up in paper towels and place them in a box. If you have a lamp, clean it using water and vinegar, allow it to air dry.  

Step 3: Remove the decorations

Prepare the decorations for storage by cleaning them using a 10 percent bleach and water solution. Once they air dry, wrap them in packing paper and store them in a clean, dry environment. As for the gravel, soak it in boiling water for 5 minutes. Allow the water to cool and then air dry it before returning it back to the tank. 

Step 4: Cleaning the tank and storage

The last step is to clean the aquarium itself. Use the steps we spoke about above to rid the tank of algae and then soak it in a vinegar and water solution for about an hour. Rinse it out and allow the tank to air dry before preparing it for storage. 

Store the empty tank in a box whether it is the one it came in or any box you might have lying around. Make sure to line the box with packing paper before you put the tank inside. If you are moving, then add some padding around the tank to protect it during transit. Ensure that you seal the box 

Buyer’s Guide

The Cleaning King team knows how common it is for new pet fish owners to have one or two bad experiences with their first aquarium. If you are at the point of giving up don’t because we’ve put together this awesome buyer’s guide to help you navigate your way around cleaning your aquarium.

Taking into account these factors will not only help you avoid mistakes, it will also assist you in planning your cleaning schedule. 


Never underestimate the cost of purchasing and maintaining an aquarium. Buying substandard or old equipment will put your fish in danger. Cutting costs when buying cleaning products might also cost you your fish. An aquarium can set you back at least $150 to $200, and you might need the same amount to maintain it depending on the size of the tank and the type and number of fish you have. 

The best way to plan this out is to have a checklist of all the items you’d need when you buy the fish tank. This list includes all the equipment, cleaning supplies, water treatment, and fish food.


There is a huge misconception that small fish tanks are easier to maintain if you are a beginner. In reality, the opposite tends to be true. Tanks that are under 37 liters are harder to manage because toxins tend to accumulate faster when the volume of water is small.

Another disadvantage is that small tanks are prone to sudden temperature and water chemistry changes which can shock the fish. A bigger tank is more constant and can handle beginner mistakes better. 


Bigger tanks can get pretty heavy once they are filled with water. Carefully think about where you are going to place your tank because moving it around for cleaning purposes might prove to be impossible. Avoid placing your fish tank in an area that will be damaged if it keeps getting wet, for example near your desktop computer or carpet.  

Number of Fish

How does the number of fish affect how you clean your fish tank? It’s simple, the more fish you have, the more waste you’ll need to clean. If the number of fish you have is in proportion to the tank size and the filtration system, then your cleaning process won’t take too long. The filtration system will keep your aquarium clean for longer.

FAQs - Ultimate Guide to Cleaning Fish Tanks

If your aquarium is new, a simple rinse with plain water is enough before you set it up. If you bought a used aquarium, you can rinse it out with hot water but if you want to take it a step further, add some non-iodized salt to the water. You can also buy an algae scraper to thoroughly clean your second-hand fish tank. 

The first step is to remove everything from the tank, this includes the decorations. Soak the inside of the tank in a warm water and bleach solution to kill off bacteria. Allow this mixture to sit for about 10 minutes and then rinse it out with water. Let the tank air dry for a few hours, make sure you replace all the substrate decorations with new ones.

This largely depends on how big your aquarium is. A small tank can take around 15 minutes to clean while a larger one can take an hour or more. It also depends on how dirty the tank is and whether you have good equipment.

It’s hard to notice that your fish tank is damaging the health of your fish if the water still looks good. A good place to look for problems is to examine the fish itself. Check for signs of distress such as a lack of appetite, discoloration, or bloating.

Without regular maintenance, your fish tank will get dirty and expose your fish to a toxic buildup of ammonia, and nitrates. While bacteria in the ecosystem can clean off some of this toxic stuff, too much of it will kill off the beneficial bacteria.