The Top 10 Best Filter for 20 Gallon Tank in 2023 (Reviews and Buyer’s Guide)

Do not let your fishes choke on their waste! Yes, waste products produce toxins that can make your fish tank a threatening environment. If left on its own for a few days, your pets may not survive. That is why filters are necessary for your aquarium as they keep it clean and healthy for a stress-free habitat. But then comes the question, which filter is best for you?

The numerous options can make you dazzled. You may find it hard to choose between strong filtration power or hang-on-the-back feature.  No worries, we will review some of the most popular filters so you can narrow down on the best filter for 20 gallon tank for you.


Best pick

Aqua Clear Fish Tank Filter has the most versatile features than others, making it the best filter for 20 gallon tank. This filter provides the best mechanical, biological, and chemical filtration to eliminate toxins, dirt, and odors. The smaller fishes prefer a lower flow rate, and this filter enables you to regulate the rate without jeopardizing its performance.

The best feature of this adaptable hang-on-the-back filter is that it can operate silently, creating a peaceful environment for you. Its robust filtration process and more manageable characteristics make it the most suited pick of our list.


Budget Pick

MarineLand Penguin 100GPH Bio-Wheel Power Filter is budget-friendly when it comes to keeping your tank clean. Every characteristic of this filter has been designed for convenient and straightforward use.

It provides maximum water flow and oxygenation, and ceaseless flushing action blocks debris from building up inside the tank. Additionally, the product feature noise-reducing vented covers for a peaceful environment. If you are looking for the best filter for a 20 gallon tank with excellent performance and does not put a strain on your purse, this filter can be your pick.


Top 10 best filter for 20 gallon tank

In the following list, the top ten filters are reviewed with their pros and cons.  Going through them, you will be able to make the best choice that you will not regret. Let’s dive in!


1. Aqua Clear Fish Tank Filter

Aqua Clear - Fish Tank Filter
  • Aquarium filtration system that offers superior contact time with filter media and energy efficient pump lowers...
  • Quick and easy installation; we recommend that you clean aquarium filter every 2 weeks for maximum operation and...

The product has a unique multi-stage filtration method that carries out mechanical, chemical, and biological filtration, ensuring a stress-free environment for your aquatic animals. It has thousands of positive feedbacks from users worldwide because of its slender frame. Compared to other filters you will see in this list, this product offers excellent contact time with filter media, and its energy-efficient pump reduces the operating costs.

Often, some sensitive fishes and plants require a slower water flow, and the filter allows you to control the tank’s water flow without compromising the filtration performance. It preserves the bacteria necessary to eliminate ammonia and nitrite, providing the tank’s inhabitants a healthy living condition. It is efficient in creating a sound-free environment when water drops into the tank; thus, you will never be bothered when operating.

It is easy to install and clean the filter. One of the best things about this product is the large filter media box that adds plenty of media and filter floss for polishing. If you own a 20 gallon fish tank, this is the best filter for your fish to thrive.



  • Offers excellent contact time with filter media
  • Quick and easy installation
  • Implements optimal filtrations
  • Provided with additional features
  • Long-lasting



  • You are required to clean the filter frequently.
  • Not self-priming


2. MarineLand Penguin BioWheel Power Filter100GPH

MarineLand Penguin Bio-Wheel Power Filter
  • WITH ROTATING BIO-WHEEL: Patented Bio-Wheel technology provides excellent wet/dry biological filtration.
  • MULTI-STAGE FILTRATION: Delivers mechanical, chemical and biological aquarium filtration to maintain a clean aquatic...

This is another top of the range option in the best filter category for 20 gallon tank that you may want to have a peek at if you are seeking a dependable and dynamic filtration system. One of the best features of this filtration system is it keeps the tank safe for aquatic lives by offering the best performance in keeping the tank clean.

Its technically advanced system operates in three stages of filtration, mechanical, chemical, and biological. The ready-to-use filters eliminate any odors, discolorations, and debris from the tank keeping the tank clean. The Bio-wheel operates at its best at removing the lethal ammonia and nitrite from the water and ensuring necessary bacteria to grow that allows a healthy condition for the tank residents.

This simple and powerful filtration system reduces the hassle of air pumps, valves, tubing, or air stones. It requires the easy steps from the user manual to set up the filter and can be used simply by hanging it onto the tank’s back. Each filter comprises of a premium activated Carbon for the highest productivity. The filter is approved by hundreds of customers, claiming it the perfect pick within a budget limitation.



  • 3-stage filtration system
  • No virtual set up required
  • Activated Carbon for maximum efficiency
  • Double-vented cover for quiet operation
  • Adjustable water flow using a mid-level strainer



  • Need to maintain an adequate water level
  • The pump may lose power.


3. Tetra Whisper EX Silent MultiStage Power Filter for Aquariums

Tetra Whisper EX Silent Multi-Stage Power Filter for Aquariums
  • WHISPER QUIET: The Tetra Whisper EX Power Filter provides silent, multi-stage filtration for clear, clean water.
  • FAST SETUP: Sets up easily right out of the box – no priming required.


For over a half-century, Tetra has been a famous brand among fish lovers for its easy solutions and excellent products. It is the best filter for a 20 gallon tank and has gained many positive reviews and recommendations from its customers. You can buy this versatile system for both terrarium and aquarium, and your fish will swim in the clean and refreshing water.

You can use a piece of aquarium filter foam to reduce the water flow if you have delicate fishes, and lessening the flow will not affect the filtration. The flow rate generates oxygenation, while the motor works efficiently. For best performance, the water level must stay above the minimum level line. The drawback is that the filter does not live up to its name; it may make a bubbling sound that can irate you.

Unlike other filters, it directs water through a recurring volume of floss to eliminate dirt. The carbon inside eradicates smells, discoloration, and contaminants. The Bio-Scrubber removes ammonia and nitrites that can harm your fish.



  • Maximum oxygenation
  • Multi-stage filtration system
  • Bio-scrubber last forever unless you lose them
  • Easier installation with Timestrip technology
  • Powerful filtration



  • Can vibrate because of the strong water flow
  • Makes bubbling noises


4. Fluval C Power Filter

Fluval C Power Filter
  • 5-stage clip-on power filter designed for freshwater and saltwater aquariums between 10 and 30 gallons
  • Two mechanical stages trap large and fine debris, foams easily slide out for quick cleaning


This filter can be described simply: elegant. Yes, the device is by far one of the most eye-catching filters. It can clean the water six times in an hour with its 119GPH (gallon per hour). Additionally, you can adjust the flow rate if you have small fishes or at feeding times or cleaning the tank. The best part is the trickle filter that ensures the filtration is not affected when the rate is turned down.

There are several reasons why this is the best filter for a 20 gallon tank; however, the primary reason is its five-stage filtration system. Unlike all the other filters, which usually have a 3-stage filtration, this device employs five. The first two stages implement mechanical filtration, followed by a chemical filtration, and lastly, the two steps complete a biological filter.

Compared to some other similar devices, it does not take up too much space inside the tank, giving the fishes room to move smoothly. With its efficient ways, it keeps your tank stress-free by removing toxic waste and impurities, it also ensures a healthier tank with sparkling clean and clear water.



  • Remarkably high flow rate
  • Adjustable water flow
  • Moderately long-lasting media
  • Quick and easy to install
  • 5-stage filtration for crystal clear water



  • Can be a little loud
  • Maintenance can be tricky.


5. Whisper IQ Power Filter for Aquariums, With Quiet Technology

Whisper IQ Power Filter for Aquariums, With Quiet Technology
  • QUIET AQUARIUM FILTER: The Tetra Whisper IQ Power Filter with Stay Clean technology contains a sound shield for quiet...
  • SELF PRIMING: Submerged motor starts up with no priming required.


If you are looking for an effective and noise-free filtration system for your tank, this filter can be the perfect pick for you. It utilizes advanced technology for effortless maintenance and a healthy environment for fish. A sound barrier separates the motor from the filter to offer you a peaceful background.

Like the other filters, it also has a bio-scrubber that encourages beneficial bacteria to eliminate toxic ammonia and nitrite. A submerged motor and adjustable intake are there to fulfill your tank needs. The filter is ideal for both freshwater and saltwater fishes.

It helps diminish the growth of algae on aquarium glass, collects tiny dirt particles, and maintains pH levels to limit crackups, ensuring a more comfortable aquarium experience for you. The product has been positively rated by thousands of its users and recommended to others.



  • Sound shield for quiet filtration
  • The submerged motor starts up with no priming required.
  • Maintain healthy pH levels
  • Easier preservation of bacteria for healthier fish
  • Uses large-sized filter cartridges



  • Need to change cartridges monthly
  • Has a large build


6. Aqueon Quietflow E Internal Power Filter for 20 Gallon Aquarium

Aqueon Quietflow E Internal Power Filter for 20 Gallon Aquarium
  • Efficiently cleans and filters water
  • Easy to install using suction cups and/or hanging clips


Check out the Aqueon Quietflow E Internal Power Filter while looking for the best filter for a 20 gallon tank. Aqueon is a trusted brand, reviewed by thousands of consumers worldwide. One of its most exquisite products is this power filter, which operates efficiently to maintain your pets’ habitat.

This design offers biological, chemical, and mechanical filtration. Biological filtration eliminates ammonia and nitrite that can be toxic for your aquatic animals. Like all other filters, this model’s chemical filtration also removes odors, discoloration, and contaminants from the water. The dirt particles and debris are separated using mechanical filtration.

Like most filters, it is also easy to install and handle using hanging clips or suction cups. For those who are interested in a filter that does not require much work to install, this is the most suitable choice for you. Additionally, the filter controls the self-priming operation that automatically runs after cleaning or a power outage.



  • Easy to hang with suction cups or clips.
  • Vertical adjustment for efficient cleaning.
  • Economical and easy to install.
  • Auto-start pump and self-priming.
  • 3-stage filtration system



  • The motor might make a humming noise.
  • Small fishes get trapped.


7. Aquarium Technology HydroSponge Filter II

Aquarium Technology, Inc. Hydro-Sponge Filter
  • Experience crystal clear water, radiantly healthy freshwater or saltwater fish, and whisper-quiet, high flow filtration...
  • Quiet and easy to clean - simply rinse and squeeze in used tank water (not tap water!) to maintain nitrogen-fixing....


Hydro-sponge filters are known for advanced architecture, elaborate features, modular configuration, and affordable pricing. This is a simple filter where water is drawn through the large sponge, using either a powerhead or an air pump. This gentle pull catches fish feces and other wastes, keeping your tank clean. The product has earned many positive feedbacks from its users.

The sponge material provides a large surface area for the beneficial bacteria to grow and carry out the nitrogen cycle. The cycle needs to be carried out to remove ammonia and nitrite; otherwise, the fish will die in the toxic environment. Further, the filter is entirely noise-free, making just only a low, pleasant bubbling.

Unlike other filters, the sponge acts as a perfect medium for both biological and chemical filtration. It is easy to maintain the filter and takes just minutes to install the device. Though the sponge is essential, it is a bit of an eyesore. It may disrupt the view of your aquarium. For this, you may hide the sponge by large aquatic plants.



  • Does not need constant cartridge replacements
  • Easy to install and clean
  • Ideal for shrimp tanks
  • Moderate filtration power
  • Longer sustainability



  • Large in size
  • No chemical filtration


8. PennPlax Cascade Hangon Aquarium Filter With Quad Filtration System

Penn-Plax Cascade Hang-on Aquarium Filter With Quad Filtration System
  • QUIET & EFFICIENT: The Cascade 300 Power Hang-On Filter quietly delivers crystal clear water throughout the aquarium....
  • ACCOMMODATING: The adjustable flow knob allows for increased or decreased water flow at will, which is extremely helpful...


This filter delivers 100GPH of crystal clear water for your fresh or marine aquarium, and its powerful filtration removes ammonia and nitrite, providing a healthy habitat for the fishes. It also ensures a suitable surface area for anaerobic bacteria to grow, which is beneficial to the tank’s living things.

The flexible flow rate and the adjustable intake tube enable you to manage the filter to your specific efficiency requirements. This filter’s flow rate does not cause much agitation in the water at its lowest setting. The water flow power can also be altered by keeping the tank’s water level almost to the top. Furthermore, the disposable cartridges provide for simple and easy aquarium maintenance. Although it is a potent filter, it makes a minimum sound while running.

The device is trusted by its consumers worldwide and has received a significant number of positive reviews. Its smaller size assures that the tank is not too crowded while its beautiful exterior intensifies the appeal of your aquarium.



  • Adjustable flow knob
  • Powerful Filtration
  • Takes less space inside the tank
  • Easy to maintain
  • Minimum noise



  • Tend to stop working randomly
  • Cartridges often need replacement.


9. Marina Power Filter

Marina Power Filter
  • Efficient Filtration: The Marina Slim S20 Power Filter's unique compact and slim design provides both practical and...
  • Features: The filter comes with an adjustable flow control so you can adjust the water flow level in your tank....


When you are buying something, you might want it to be unique. This particular filter is perfect for you if you are opting for an outstanding product. It is an entirely transparent filter that not only enhances its attractiveness but also enables you to see whether the media needs replacing.

Unlike canister and internal filters, you can hang this one in the back of the tank. It does not take up any space, leaving the fishes to enjoy the clean and refreshing water. Furthermore, it is a self-priming filter, a feature we all appreciate. Speaking of appreciation, the noise-free operation of the filter is also something we can acknowledge.

Compared to other filters on this list, the device has a moderate filtration power, but it can still clean the whole of a 20-gallon tank up to three times in an hour. This feature can be useful if you own small aquatic animals. Like most of the products, it also uses a three-stage filtration process to ensure a healthy home for your loving fishes.



  • Easy to support and install.
  • See-through exterior
  • Does not make the tank crowded
  • Reasonably tranquil
  • Adjustable flow rate



  • Durability is uncertain.
  • May vibrate with prolonged usage.


10. AquaTech Power Aquarium Filter with 3Step Filtration

Aqua-Tech Power Aquarium Filter w/ 3-Step Filtration
  • POWER FILTER: Advanced 3-step filtration
  • VARIETY OF SIZES: For aquariums 5-15 gallons, 10-20 gallons, 20-40 gallons, 30-60 gallons


Filtration necessary for aquariums, even if they have only a few fishes. And you will need a smart and advanced filter to keep your fish safe from their food and feces. With its three-step filtration system, this product will mechanically, biologically, and chemically filter your tank to maintain a stress-free environment. It will remove dirt particles, odors, contaminants, and toxic waste like ammonia and nitrite while providing an area for beneficial bacteria’s growth.

The filter is easy to maintain and install. Its molded ribbed back ensures maximum water-to-carbon contact keeping the water crystal clear. Unlike some filters, the cartridges may require replacing because the Carbon deactivates overuse. But overall, it has fair durability. It has strong suction power too. Although it may make a bubbling or gurgling noise while operating, many users have reviewed it to be the best filter for a 20-gallon tank, making it reliable to pick.



  • Three-stage filtration
  • Strong flow rate
  • Simple maintenance and installation
  • Maximum water to carbon contact
  • Comes with two filter cartridge



  • May stop working
  • Make unwanted noises


Buying Guide for best filters for 20 gallon tank

Some of the necessary factors you have to keep in mind while purchasing a filter:



As for a 20-gallon tank, a comparatively smaller tank, you should choose a filter with a slender frame. You might not want the filter to take up all the space and make the filter congested. Additionally, with a small filter, you could spare some extra space to decorate your tank with plants and fishes could swim freely.  Also, a bigger filter might lessen the appeal of the aquarium. You could look at HOB filters because they can be hanged at the back of the tank, allowing space for your fish and decoration.


Type of fish

When deciding on what type of filter you want, you may want to look at what kind of fish you are keeping in the tank. The requirements of the product will vary depending on freshwater or saltwater fish. There is no need for biological filtration; only mechanical and chemical will suffice. Thus, hang-on, canister, and wet-dry filters work best fr freshwater. On the other hand, for a considerable collection of fish and turtles in your tank, you will need all the filtration steps plus powerful filtration. In this case, under gravel filter is the best, although there is a slight visual drawback going with it. So, choose your filter according to your needs.


Quiet Operation

Everyone with an aquarium is searching for a filter that does not generate a lot of noise when running. According to some people, canisters filters are best for sound and vibration-free cleaning of the tank. As canister filters can take up some space, you may want to be wise about the decision. With this said, users claimed that they have a better sleep with the filters’ soothing, bubbling sound.


Filtration process

The filtration power depends on the GPH (gallon per hour), so you can check the GPH of a filter before considering it. If you have small fishes or shrimps, you will have to choose a filter with lower GPH or with an adjustable flow rate. Make sure it can keep your tank clean using at least a three-stage filtration process, biological, mechanical, and chemical, to remove toxins, odors, and wastes.



One of the most beneficial features of a filter is its self-priming process. Self-priming allows the device to turn on automatically after a power interruption or cleaning. This may help as sometimes you can forget to switch on the filter, and the water can get dirty and toxic, harming your pets. It should have a compact area but easier to dismantle parts for ease of cleaning. Some filters need frequent services, and if you have to hire somebody to service your aquarium, be prepared to feel a strain on your budget every two to four weeks.


Frequently Asked Questions

1. How 20-gallon tank filter works?

Generally, the filters work in a 3-step filtration process. Mechanical, biological, and chemical filtration process eliminates toxic waste, dirt particles, odors, and discoloration from the water.


2. Why is the aquarium filter necessary?

Without a filter, food, urine, and feces from the fishes will make the water dirty to where the fish cannot survive. Filter helps keep the water clean and healthy by ensuring beneficial bacteria that remove ammonia and nitrite.


3. What should be the GPH for a 20-gallon tank filter?

The GPH should be at least four times the tank capacity; thus, for a 20-gallon tank, you will need at least 80GPH filter. Moreover, the higher is the GPH, the stronger is the filtration rate.


4. How frequently I have to change the filter media?

The carbon filter needs to be changed once a month, sponge every two months, and biofilter every three months. We would recommend not changing more than one filter at a time.


5. Is there any way to reduce the noise of the filter?

If you maintain the water level correctly, the filter should not make loud noises. You can also rinse the impeller as sand, hair, or any debris can get stuck to it. Just rinse it water, do not use soap.


6. What to do if there are algae on the submerged filter?

Take out the filter, dismantle the parts, and clean each carefully without soap.


7. Can I add a sponge filter to the intake for little fishes?

Yes, you can. You can use sponge media or filter floss; just make sure to clean or replace it when it gets clogged.


8. Can I use these filters if I have turtles in my tank?

If there are turtles, you have to keep the water level at least 3-4inches below the tank’s top.


9. Do I have to fully submerge the filter or can have the top sprout out of the water?

The tube can be extended above the water surface, but the rest of the filter has to be submerged.


10. What is frustration-free packaging?

The packaging is easy to open.



The good news for consumers nowadays is the increased options for aquarium filters with various features that serve specific demands. There is a common characteristic for all these filters, regardless of their shape, size, and brands, their utmost priority is to keep your tank fresh and healthy for your colorful pets. Hopefully, you can choose one that works best for you as they have different merits and demerits. If you still have some dilemma, you can check out Amazon or fish stores for the best filter 20 gallon tank; prices and warranty can help concretize the options more.

Leave a Comment