Best Fish Tank Filters for 20 Gallons

Top 10 Best Fish Tank Filters for 20 Gallons In 2022

What are the best fish tank filters for 20 gallons? Aquariums are closed-off ecosystems that must be sustained through the efforts of the aquarist. In this respect, aquarium filters are a valuable device for maintaining good water conditions in the tank.

The filter you choose for your aquarium must be rated for the water volume the tank can hold, and in this article, I will focus on the filters best suited for 20-gallon aquariums.

I’ll talk about 10 of the best filters for 20-gallon tanks along with their pros and cons, so you can choose the ideal filter for you.

What Type of Filter to Choose for 20 Gallon Fish Tank?

Best Fish Tank Filters for 20 Gallons.
Best Fish Tank Filters for 20 Gallons

With regards to medium-sized aquariums, there are a few filter options to consider:

Hang-on-Back Filter (HOB)

HOB filters are possibly your best choice with regard to 20-gallon aquariums. These filters easily slide onto the edge of the aquarium, they’re easy to maintain and offer mechanical and biochemical filtration.

They’re also affordable and silent as opposed to larger filter systems. Additionally, hang-on-back filters also efficiently filter the water volume they’re rated for.

Internal Filter

Internal filters are another option available for aquarium filtration, however, their efficiency isn’t comparable to that of HOB filters.

Internal filters are also more difficult to clean and maintain, but they can be a good option for small aquariums or terrariums where strong water flow isn’t needed.

Canister Filter

Canister filters are usually filtration powerhouses. They’re strong filters that can tackle the filtration of large aquariums. They sit outside of your aquarium, making a decent lot of noise compared to HOB filters.

For a 20-gallon tank, a canister filter might be overkill. Canister filters are more suited for aquariums north of 50 gallons, but you might find canister filters rated for smaller aquariums as well.

Therefore, in the event that you have a 20-gallon aquarium, a hang-on-back filter will be perfect for it. Essentially choose a HOB filter that is rated for 20 gallons. You’ll have the filter going in a matter of moments and keeping up with it over the long haul will be easier.

Choosing Filter for 20 Gallon Aquarium

Best Fish Tank Filters for 20 Gallons
Best Fish Tank Filters for 20 Gallons

Regardless of whether you’ve decided on investing in a HOB, internal filter, or canister filter, you’re still going to need to ensure it’s correctly rated for your aquarium.

A good rule of thumb in choosing a filter size is that the water in your aquarium ought to go through the filter four times each hour.

In this way, on the off chance that you have a 20-gallon tank, you ought to get a filter that offers a flowing pace of something like 80 gallons each hour.

If all else fails, always go for a bigger size. Undersizing your aquarium isn’t recommended and oversizing it is always a better option.

What you ought to be mindful of is that you might open your fish to an excess of flow, but because some aquarium filters have underlying flow control mechanisms, you can easily choose a lower setting to accommodate the needs of your fish.

10 Best Filters for 20 Gallon Aquariums In 2022 Reviews

Assuming you’re looking for best-in-line filters for your tank, here are my top picks for the best filters for 20-gallon aquariums:

1. Aqua Clear – Fish Tank Filter

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  • Silent operation and durability
  • Possibility to customize filtration media
  • Mechanical and biochemical filtration
  • Adjustable flow rate
  • Easy installation


  • AquaClear filter media bags are slightly more expensive, but you can use your own media mix
  • Maintenance is required for the propeller box as debris may get trapped

This HOB filter is a calm and efficiently operating filter that I recommend for anyone looking for a power filter for their 20-gallon aquarium.

The filter media that comes with the Aqua Clear contains the AquaClear froth insert, the AquaClear activated carbon insert, and the BioMax Ceramic rings for a 3-stage filtration process.

Because of its base-up design, this filter ensures that all your aquarium water goes through the filter bed, a system that reminds of the mode of operation specific to canister filters.

Another viewpoint that I find it’s worth focusing on about this HOB filter is the large filter compartment, which allows you to customize your own filter media would it be advisable if you wish so.

A further extraordinary feature of the Aqua Clear is the protected pre-filtration system that empowers you to control the flow rate despite everything accomplish up to half filtration of the water in the chamber multiple times.

2. GRECH CBG-800 5W UV Sterilizer Hang-On Back Filter

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  • HOB with UV sterilizer for protection against algae and bacteria;
  • Adjustable flow and silent operation;
  • Easy installation;
  • Helpful surface skimmer;
  • Multi-stage filtration for a clean and clear aquarium.


  • The media basket design is a bit too tight;
  • The carbon filter that comes with it isn’t top quality, you may need to use your own.

This external HOB filter features a 5 W UV sterilizer that assists with the elimination of bacteria and algae, which is perfect in the event that your fish aren’t in any case algae eaters.

Besides the UV purifier, the Grech HOB filter also features bio-media and activated carbon media, therefore, offering mechanical and biochemical filtration.

Another useful feature of this aquarium filter is its surface skimmer, which disposes of surface movies.

On the off chance that you were pondering the UV sterilizer can be turned on/off autonomously, so in the event that you don’t need to use it you can turn it off and turn it on when you truly do need it.

The flow rate is adjustable, and the compact design allows easy installation without the need for extra plumbing or tools.

I recommend this filter for anyone battling with a tank inclined to algae blossoms as it’s extremely proficient at managing obstinate algae issues.

3. Fluval C Power Filter

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  • 5-stage filtration;
  • Easy installation, assembly & disassembly;
  • Possibility to use own filter media mix;
  • Adjustable water flow.


  • The impeller is a bit difficult to clean;
  • Spout that trickles water on bio-media can clog up easily;
  • Filter replacement is easy, but you need to remember the different replacement dates that vary.

This is another HOB filter for 20-gallon aquariums that I demanded remembering for this top 10 rundown of best aquarium filters because of its extraordinary incentive for cash and has a 5-stage filtration.

This clasp-on the filter with a particular media compartment allows you to clean every compartment each in turn. The media compartment is large and allows you to use your own media blend.

The Fluval C3 filter is rated for aquariums somewhere in the range of 20 and 50 gallons. This filter also has a flow rate agent that allows you to lessen or customize the flow rate to the required levels without thinking twice about filtration efficiency.

The 5 filtration stages can be broken down as follows:

  • Polyfoam media replaceable every 4-6 weeks;
  • Biological c-nodes are replaceable every 6 months (only 50% of quantity, not all at once);
  • Activated carbon media replaceable every 2-4 weeks;
  • Bioscreen replaceable every 2-3 months;
  • Motor o-ring replaceable yearly.

4. Fluval Underwater Filter

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  • Multi-stage filtration;
  • 3-way flow control;
  • Vertical or horizontal installation;
  • Ideal for freshwater applications, reptile, and marine environments;
  • Rated for 20-40 gallon aquariums.


  • The media compartment is a bit too small;
  • The U3 model may not be enough for a 40-gallon tank, which may better benefit from the U4 model.

This internal filter from Fluval is rated for 20-40 gallon tanks. It introduces easily and offers mechanical, compound, and organic filtration.

It tends to be mounted upward or evenly assuming water levels are lower, which is ideal for tanks with turtles that are filled just most of the way because they feature a lounging stage.

Because this is an underwater filter, filtration is completed beneath the water level. Noise is negligible, just the silent murmur of the impeller bringing water into the system.

Then, at that point, there’s the option to set the flow yield in 3 distinct positions to meet your specific needs:

Assuming you need profound water fomentation, you need to choose the Bottom Output setting. For a delicate and all the more even flow, choose the Spray Bar setting. The Top Output setting is for the most extreme dissemination and oxygenation.

5. MarineLand Magnum Polishing Internal Canister Filter

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  • Huge processing power (290 gallons/hour);
  • Ideal for large aquariums;
  • Offers all three types of filtration;
  • Customizable media because of large media chambers;
  • Easy to clean, self-priming.


  • Not compact takes up a lot of space in the aquarium;
  • Fairly noisy;
  • Most suited for 50+ gallon aquariums.

Designed to filter water in aquariums up to 97 gallons in size, this MarineLand canister filter is one of the better canister filters out there.

This is a strong filter that comes with 3-stage filtration, eliminating garbage, poisons, tones, scents, and more through substance, mechanical and organic filtration.

The filter features a double chamber for filter media, which allows you to make your own blend of filter media relying upon your filtration necessities.

As an internal filter, the MarineLand canister filter is a sub, and that implies it will occupy some room in your aquarium.

What’s perfect about it is that it’s self-preparing, taking out the need for manual preparation. Cleaning is very easy because of the easily removable top.

6. Aqueon Quietflow Internal Power Filter

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  • Quiet and has good processing power;
  • Offers 3-stage filtration;
  • Cartridges can be easily changed;
  • Vertical or horizontal installation.


  • Takes up some space in the aquarium;
  • The smallest filter size lacks mechanical and biological filtration.

Ideal for aquarium or terrarium use, this Aqueon internal power filter offers three stages of filtration. It comes in various sizes, contingent upon how large your aquarium is.

The attractions cups furnished with the filter unit make it easy to introduce it. You can introduce it in an upward direction or evenly with an adjustable return flow rate.

It’s a peaceful filter, that is lowered in water and requires no preparation. Just fix it in your aquarium with the attractions cups, plug it in, and it’s all set!

Cartridges in the Aqueon are easy to supplant, there just isn’t any problem with support, so you can add that to the rundown of benefits.

Concerning the filter media inside the system, the Aqueon Quietflow contains a thick froth media for filtering out flotsam and jetsam and particles, activated carbon media for compound filtration, and a BioGrid for natural filtration.

7. Fluval 106 External Filter

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  • User-friendly canister filter with easy maintenance;
  • Multi-stage filtration;
  • Aquastop valves for hassle-free interventions;
  • Instant priming, no manual siphoning needed.


  • Powerful flow that needs to be mitigated with spray bar if a low flow setting is required;
  • Impeller issues have been reported after 6-12 months, however, a warranty is provided for 3 years.

This Fluval external canister filter is rated for aquariums up to 25 gallons, therefore, in the event that you’re looking for an external filter for your 20-gallon aquarium, this filter might be an extraordinary option for you.

We should see the features that make this canister filter a filter to consider for your freshwater or saltwater aquarium:

  • It offers multi-stage filtration, which is guaranteed by the twin froth pre-filters that clear your water of garbage and forestall the obstructing of different media, the two other synthetic and organic filters;
  • Free filter modules permit easy admittance to the media and easy changeover;
  • AquaStop valves guarantee the interference of water flow without spills or disengaging hoses;
  • Sound-hosed impeller for calm operation;
  • Comes in four distinct sizes.

8. Penn Plax Cascade Canister Aquarium Filter

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  • Multi-stage filtration;
  • Easy set-up, comes pre-loaded with filter media;
  • Easy push-button primer;
  • Adjustable flow rate;
  • Sturdy, tip-proof design.


  • Tubes can be a bit rough to connect;
  • Some priming issues were reported by users.

This specific Recommended for aquariums up to 65 gallons, the Penn Plax Cascade canister filter offers 185 gallons each hour of filtration. It’s available in larger sizes too for bigger aquariums, where more filtration power is required.

Fire up is made easy by the pushbutton preliminary, while the pool-style hose clips make installation speedy and bother-free.

Flow rate can be changed with cut-off valves and the two media bushels can be customized as they’re sufficiently open to accommodate your own filter media.

For a canister filter, it’s one of the calmer ones. Whenever set into a bureau, you won’t hear it by any means, which is incredible information for those with large aquariums.

Flow valves autonomously turn 360 degrees for easy maneuvering. The splash bar and directional spout are both included with the filter pack.

9. Aqueon QuietFlow Canister Filter

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  • Flexible and easy setup
  • Multi-stage filtration
  • The quiet and functional unit
  • Easy access maintenance
  • Spray bar included


  • No issues were reported so far

Giving a flowing pace of 200 gallons each moment, this canister filter from Aqueon is designed for filtering water in saltwater or freshwater aquariums up to 55 gallons.

It comes preloaded with organic (Bio-Balls, Bio-Ceramic Rings), synthetic (Activated Carbon), and mechanical (Coarse Foam) filter media for a careful and complete filtration.

If the preloaded filter media blend isn’t what you need, you can customize it, and add your own media to the media chambers.

For those needing a delicate flow, the shower bar is incorporated with the filter unit along with two different connections.

The filter is easy to set up and the remembered hang for the backwater polishing unit makes support speedy and easy.

10. Polar Aurora Free Media External Aquarium Filter

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  • The silent operation even if it’s a canister filter;
  • Self-priming, no manual siphoning needed
  • Can filter up to 265 gallons per hour
  • Useful surface skimmer
  • Possibility to use with own filter media


  • The newer model has no UV light (older models included a 9 W sterilizer lamp)
  • A fairly sizeable unit compared to HOB filters.

Regardless of whether you’re curious about canister filters, the user-accommodating design makes this external aquarium filter a helpful choice in any event, for fledglings.

The Polar Aurora is rated for up to 75-gallon aquariums, offering a 3-stage filtration. The 3 media plate makes it easy for you to pick your own choice of media and use that in the plate.

Canister filters always pack more power than their HOB partners, so for those needing a more delicate flow the Polar Aurora ships with an adjustable splash bar that permits easy change of flow rates.

Similarly, as with the other canister filters I evaluated in this article, the Polar Aurora is also a self-preparing one, therefore, there is no need for manual siphoning.

FAQs – Best Fish Tank Filters for 20 Gallons

How To Choose A Flow Rate For A 20-Gallon Aquarium?

To decide the right flow rate for your fish tank, it is fundamental to first know the size of your aquarium. When you have that worth, duplicate it by four. The end figure will be the flow rate (in GPH) expected by your aquarium to remain clean.

On the off chance that you have a thickly involved tank with heaps of plants and small fish, especially with gadgets, for example, CO2 diffusers, it is recommended to keep a low flow rate in your aquarium. While some fish like danios and hillstream loaches incline toward higher ebbs and flows and a higher flow rate.

How Can I Efficiently Use A High-Flow Filter For My Tank?

Before you buy an aquarium filter with a high flow rate, it is fundamental to consider regardless of whether it will suit your marine life. That being said, we recommend incorporating some hardscape structures in your fish tank. This will assist with making quiet zones where drowsy fish, like puffers, can escape the high flow and rest when needed.

Do Filters Cause Harm To My Fish?

Filters are basic to the soundness of the fishes inside your aquarium. They are not destructive for however long you’re not using a filter that creates a powerful current inside your fish tank. All things considered, the filter might overreact your fish.

Filters with bigger gulfs ought to also have a pre-filter to keep minuscule animals from getting sucked into the filter or stuck against the air consumption.

Conclusion – Best Fish Tank Filters for 20 Gallons

Despite the fact that I recommend a hang-on-back filter for most 20-gallon aquariums, there are many canister filters and internal filters that you shouldn’t excuse as a choice to HOB filters.

As may be obvious, all filters have their pros and cons, but the filters I checked on as best filters for 20-gallon tanks all have features that recommend them as a dependable choice.

All things considered, the filter you choose ought to have the option to efficiently filter the water volume in your tank and ideally offer 3 layers of filtration — mechanical, substance, and natural.

Noise levels and upkeep are different perspectives to consider, but the filters I recorded above are known for their tranquil operation and simplicity of support.

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