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Looking for the world’s messiest pets? Look no further than the fish tank. Dogs may need to be let out a few times per day, but fish and other aquatic pets need 24/7 filtration support to keep their habitats clean! You may as well look for the best canister filter to simplify things for yourself.

If you’re newer at fish keeping (or whatever else you have in your tank besides fish), canister filters may seem intimidating. They’re used by most professionals, but that doesn’t mean they’re difficult to use or complex at all. In fact, canister filters actually do the job so well that you hardly have to do anything for the tank to stay clean.

Canister filters can give you a break on tank cleaning, but only if you pick the right one. If you get a bad filter, it won’t be any better than anything else.

Learn more about how to pick the right canister filter, how they work, and the benefits. Then, see if you can find one that looks good from our handy list of reviews for some of the top-rated, best canister filters available now.

Tips on Finding the Best Canister Filter

To get the best canister filter for your aquarium setup, you need to understand a little bit about canister filters first. Here are the main things you need to look at on a canister filter:

Flow Rate

This is the key measurement that matters for canister filters. The flow rate indicates how many gallons of water the pump can push through the filter in an hour. You’ll see this measured in gallons per hour, usually abbreviated as GPH.

For a canister filter, you want the flow rate to be at least 3 times the size of the tank, though 4 times is better. This means it will be able to filter the entire tank’s water at least 3 times within an hour. Whatever your tank size is, look for a filter with a flow rate at least 3 times as large.

Filtration Stages

Aquarium filters can provide up to 3 different types of filtration. These are mechanical, biological, and chemical. Mechanical filtration takes out the solid waste from the tank. Biological filtration builds up helpful bacteria to manage algae and ammonia. Chemical filtration treats water quality issues that can affect fish health and water clarity.

Most canisters have at least 3 filtration stages, which can be customized to include all different filtration types. For many tanks, having all 3 different types of filtration is important to balancing out the tank and maintaining health in the long run.

Filter Media Type

Depending on the design of the canister, the type of filter media used inside each filtration stage will vary. Larger canisters are usually set up with baskets that can contain loose filtration media. Some canisters are designed for cartridge-style filter media, though this is not as common.

Loose media and sponges give you a wide variety of media refill choices. If you’re limited to cartridges, it can cost more and restrict your options. The best canister filter choice for your tank will be able to use any filtration media you need to keep your tank water quality high. Ultimately, that’s the goal for any filter.


Canister filters do not hang on the back of the tank, nor do they sit inside the tank itself. They have to be stored outside of the tank, usually below it. You’ll need space to store it so it can work well.

Most canister filters are cylindrical and tall. Some are rounded rectangles. All canister filters should be rounded on the inside without sharp corners. This helps prevent water from bypassing the filtration media inside and keeps the system working efficiently.

Top 6 Best Canister Filters for Aquariums

If you have a smaller fish tank (or larger), our selections have other sizes for you to choose from. If you have trouble making a selection feel free to ask for help by dropping a comment below.

1. Fluval FX6

This canister from Fluval is one of the most powerful models around. The large black cylinder has a durable, high-tech design. It’s matte black in color with striking red accent pieces from top to bottom. Here you can find the Fluval FX6!


  • Solid, durable construction for great longevity
  • A strong pump and impeller design work well together
  • Automatic priming to help you start it easily, plus an automatic air expulsion system
  • Enormous interior capacity for filter media
  • Simple maintenance and cleaning routine


  • Oversized for many tanks under 75 or 100 gallons
  • Can be difficult to accommodate

Fluval created this canister for large aquariums. Advertised for tanks up to 400 gallons, the 563 GPH flow rate and a maximum pump output of 925 GPH make it a formidable filter. It may not work perfectly for 400-gallon tanks, but it would be effective for 100 to 200-gallon tanks.

Inside, the media baskets hold a total of 1.5 gallons of filter media altogether. You can decide for yourself what to put in each basket. Baskets are well set up to hold loose media and large filtration sponges or similar.

Input and output valves conveniently connect to the top of the filter within easy reach. They are multi-directional for a simpler setup. Cutting water flow and removing the valve is done seamlessly, making cleaning a lot easier.

Surprisingly, this filter runs very quietly, despite its large size. The impeller is designed to purge water from the filter automatically, keeping it running at peak efficiency and as quietly as possible. Replacement parts are available if necessary for repairs.

Overall, there’s a high level of integrity in the design of the Fluval FX6. It’s made to last, with every piece being carefully thought out. You won’t have to do much to keep it running for months or years, as long as you’re performing regular cleaning and maintenance.

2. Penn Plax Cascade

From Penn Plax, the Cascade canister aquarium filter comes in a variety of different sizes and buying packages. You can get the 500, 700, 1000, 1200, or 1500 models. The 700, 1000, and 1500 are available in regular and elite versions. The filters are rated for a maximum of 30, 65, 100, 150, and 200-gallon tanks respectively. Here you can find the Penn Plax Cascade!


  • Large variety in buying options for tanks of all sizes
  • Media trays are easy to customize and arrange as you please
  • Tip-proof rubber stand helps this filter stay in place wherever it is
  • Simple to open or clean with easy-lift lid clamps
  • Runs very quietly


  • A considerable amount of water is able to bypass media trays
  • Included filter media is not very effective

Regular and elite versions are not different filters. The difference is what comes along with the filter. While regular versions are a blue filter by themselves, the elite versions are jet black and come with a large assortment of tubing, valves, connectors, and other accessories. Elite kits also come with Penn Plax filtration media to fill the baskets inside.

This canister is designed with baskets to hold loose filtration media or sponge filter pieces. The different sizes have varying numbers of baskets and can hold a varying amount of media appropriate to their size.

Rectangular in shape, this canister can fit easily in many cabinet spaces. The lid is designed to remove easily and snap back into place quickly for simple setup and maintenance. It’s easy to take it apart for cleaning and put it back together once you’re done. Both the input and output hose valves are located on the top, telescopically rotating for convenience.

This does not have a self-priming filter pump, but the button to prime is right on top of the canister in easy reach. You shouldn’t have to prime it more than a few times to get it up and running. Priming is only necessary when you turn the filter off and on again.

3. Hydor Professional External Filter

The Hydor Professional external filter is a sleek black canister filter with a lot of different sizing options. You can get it for 40, 75,100, 125, or 150-gallon tanks. The model numbers, 150, 250, 350, 450, and 600 respectively, refer to the number of liters each filter can cycle per hour. Here you can find the Hydor Professional External Filter!


  • Great range of sizes for various tanks
  • Longlasting, durable design
  • Strong and consistent flow rate
  • Provides great water clarity for the appropriate tank sizes
  • Runs almost silently when it’s set up properly


  • Input and output valves can get leaks after a few months of use
  • Spare parts cannot be purchased separately

Regardless of which size you get, each filter comes with a kit of necessary pieces and accessories to get it set up. You’ll receive tubing, fastening plunger hooks, valves, and filtration media. Instructions are provided to help you hook everything up correctly.

The inside of the filter uses a series of stacked filtration media baskets. Water is pushed in from the bottom and back up through all the media before returning to the tank. Both water valves are right beside each other on the top of the filter for easy access.

This is not a self-priming filter, but the priming button is right on top beside the water line valves for quick priming. You don’t have to move the filter to prime it. Just press the button a few times until all the air is cleared out of the filter, then plug it in and turn it on.

Opening and cleaning this filter is very easy. The top has a simple securing mechanism that quickly snaps back into place when you’re closing it. You won’t struggle to get it back together after you clean it or change out the media.

4. MarineLand Magniflow

From MarineLand, the Magniflow filter is available in 3 different sizes for medium to large aquariums. The smallest works in up to 30-gallon tanks, the next in 55-gallon tanks, and the largest in tanks up to 100 gallons. All the filters are dark grey and black with red accents. Here you can find the MarineLand Magniflow!


  • MarineLand provides excellent customer service when necessary
  • Very quiet operation when in working order
  • Easy to set up and store in an open space
  • Maintenance is simple and easy to get used to


  • The Air hose clamp is made from plastic and may not create an airtight seal
  • Prone to small leaks and some impeller problems after a few months

To seal the lid down, latch the top clips into place to create a watertight seal. When you want to open it again, the clips can unlatch to remove it quickly from the top. Both water input and output valves are located on the top of the filter.

As a large rectangular canister filter, this model is easy to store in a cabinet space or anywhere else below the tank. You only need to access the top for cleaning and filtering media changes, giving you added flexibility in where to put it.

Within in filter body, filter media baskets stack on top of each other according to the size of the filter. The smaller models have fewer baskets while the larger ones have more baskets. Each basket can hold a large amount of loose media or a filter pad or sponge of some kind. Media is included with the kit, so you can use the filter right away after setting it up.

5. Fluval External

One of the most popular canister filters from Fluval, you can get this in 4 different sizes: the 106, 206, 306, or 406. They are meant for tanks up to 25, 45, 70, and 100 gallons respectively. All the various sizes of the filter maintain the same basic design, with the main difference being the dimensions inside and out. Here you can find the Fluval External!


  • Filter media included with the kit for quick setup
  • Consistent, strong water flow to the tank
  • Simple to set up with the instructions
  • Large filtration sponges clear up a lot of particles


  • Lift-lock clamps can be difficult to seal completely and may need a sealant to close
  • May pump microbubbles into the tank

The filter is a tall rectangle shape made from hard black plastic. On top, the input and output valves sit next to each other on the lid. Connecting or disconnecting the lid is as simple as operating the latches on the sides. When closed, it creates a watertight seal.

In the center of the lid, the primer button helps you get the pump ready to operate. It’s not a self-priming pump motor, but the button is easy to press and doesn’t require a lot of work to get it primed and ready to turn on. The filter does not need to be primed every time if it’s only off for a few hours without being opened.

For the filtration inside, baskets stack on top of one another to give a large capacity for loose media or filter pads. This Fluval filter is compatible with any other media that fit into the baskets.

Regardless of which size filter you choose, each one comes with a kit of the necessary supplies for installation and initial setup. All the tubes, valves, connectors, and O-rings you need are included in the kit.

6. Fluval G6 Advanced Filtration System

With a unique canister design, this filter is mainly intended for larger aquariums. There are two sizes available: for tanks up to 80 gallons or 160 gallons. Both are black squares with silver accent details around the edges. Here you can find the Fluval G6 Advanced Filtration System!


  • Runs almost completely silently
  • Very little water bypass for filter media
  • The priming button is easy to use
  • The LCD display is simple to navigate and provides useful functionality


  • The flow rate is not always as high as it’s rated, with some inconsistency and lower flow
  • The hoses on top are not telescopic and take up a lot of space

Water lines attach to the top of the filter. The input and output valves are right beside each other, with one feeding water into the bottom of the filter and the other returning it to the tank. Nearby the valves, the round primer button sits in the middle of the lid. When you want to turn on the filter, you need to prime it first to get a watertight seal inside. It does not self-prime.

The lid latches closed with four clamps around the corners. These clamps seal it closed to create a watertight hold so the filter works as it should. Maintaining the filter means opening the clamps, removing the filtration media baskets, and cleaning it out. Media can easily be cleaned and changed once the lid is off.

On the front of the filter, there is a small LCD screen. You will adjust the flow rate and other settings on this screen by pressing the right buttons around the edges. The screen also gives you information from the HydroTech monitoring system, so you’ll understand what’s happening with the filtration.

Included in the kit are all the pieces you need for setup, including filtration media and all mandatory hoses, valves, etc. Also with the necessary pieces are a few optional water return accessories to help you set your water return flow just right. You get a spray bar, rim attachment, and spray nozzle. There is an optional strainer for the water intake hose.

What You Should Know Before Buying a Canister Filter

Well, I hope you agree with this list as much as I do. This might not suit you, so we prefer you to have a look at all of the details below. That will help you in choosing the best canister filter possible.

What is a Canister Filter?


Canister filters are units that work under strong pressure making them one the best aquarium filters. They are usually mounted under the aquarium and conduct all three forms of filtration. In other words, with their help, you will get complete filtration. It’s also worth mentioning that they come in two different sub-types – a complete canister filter that comes with an independent pump and a modular canister filter that needs an additional pump. The latter is especially helpful when used together with other types of filters like the wet/dry filter.

On the other hand, complete canister filters rely on –tubes for water intake and a spray bar for the return of the water. When the canister filter is mounted on the aquarium, a siphon is activated. This siphon allows the water to circulate from the aquarium to the filter. So, the water will first enter the filter and go through a mechanical media and reach the chemical media. Once the chemical filtration is finished, the water goes to the final chamber that has the biological media and this is where the nitrogen cycle is finished.

Benefits of a Canister Filter

There are many pros and cons related to this type of filter but it seems that the number of advantages is much higher. First of all, a canister filter can significantly increase the total volume of water in the aquarium system. Without any doubt, this is a positive thing due to the fact that increased water volume leads to a lower concentration of dangerous impurities like waste and food leftovers.

In addition, a bigger volume also leads to increased stability of water with fewer fluctuations in terms of water parameters in general and temperature too. Another great thing about canister filters is that the fish will get more space because they are attached to the bottom of the aquarium. Additionally, the aquarium will look more natural and more attractive because this filtration system is less visible. The presence of a rain bar allows the filter to aerate the aquarium water too.

Canister Filter Drawbacks

Of course, there are some cons linked to canister filters too. For example, they require proper and regular maintenance. This is the main reason why so many canister filter users give up on them after a while leaving them clogged and dirty which is obviously the worst solution. So, if you are planning on using a canister filter, you better be prepared to clean and maintain it regularly. According to some experts, it’s not very difficult to establish a routine like this, and even though it might look a little bit time-consuming in the beginning you will reduce the time needed for this activity after a while.

How Do Canister Filters Work?

We have already explained the basic process, but let’s go into detail. The filtration process in the canister filter starts with mechanical filtration which is probably the best among all types of aquarium filters. This is a pressurized filter which means that the water is practically forced through a refined material that can keep even the tiniest impurities. Some of these products have clear indicators about the size of particles that the canister filter can process, so take a good look at them.

The next step is chemical filtration which is once again very efficient. Once again, the reason is simple – the pressurized unit promises better results compared to other filters. In addition, users should know that it is quite easy and simple to change the kinds of chemical filtration media used in canister filters. Experts suggest the use of activated carbon even though there are some other highly efficient types of media too.

Finally, the process ends with biological filtration. The results that canister filters provide at this stage are mediocre because of the amount of oxygen found in the passing water. The lack of water-to-air contact caused by the pressurized media is the main reason for this. The good news is that there is more than one type of media used in these filters for biological filtration and some of them might be more efficient than the others. For instance, porous materials, ceramic rings, and engineered glass materials are used for this purpose.


Setting up a Canister Filter

Start by putting the output and input flow pipes on the aquarium exactly where the filter will be attached. There are cases when people need a spray bar or a directional output that should be used on the output pipe for this purpose. If there is a pre-filter, snap it onto the input pipe’s end.

Next, put the canister in its position and check the length between the output and input pipes and the ports. Use a knife or scissors to cut the hose. Choose a length that is a little bit longer than the length you’ve measured just in case.

After that, attach the ends of the hose adequately – to the output and to the input port of the canister. The filter basket/s must be filled with the media used in your specific canister filter.

Put the filter basket inside the canister in the right direction. Don’t force the basket in, make sure it fits well. Fill the canister with the recommended fill level with aged aquarium water or dechlorinated water that comes from the same aquarium.

Put the big O-ring in the water and make sure it’s wet. After that, put the ring around the upper part of the canister. Turn the device on and watch the process if you want. When you are using it for the first time, check the device for leaks.

Canister Filter Maintenance

The number of canister filter models is increasing every year and this is definitely something that we should take into account when we are discussing canister filter maintenance. The brand and the model of your canister filter, as well as the number and type of filter media used in it, will determine the maintenance process.

However, generally speaking, freshwater canister filters allow users to opt for many different filter media options. Many of these filters come equipped with cartridges, baskets, media bags, and even with separate chambers where you can place your desired media and get the specific type of filtration you are looking for. There are some filter media that must be cleaned on a regular basis, while other media varieties must be replaced. It is a smart idea to check the recommendations provided by the manufacturer in order to avoid any mistakes.

We have already mentioned before that cleaning and maintaining canister filters requires more time and effort in comparison to most aquarium filters. When you are cleaning this filter, you must put your focus on the canister and the hoses, and the impeller too. It is a smart idea to use a brush with soft bristles to scrub the hoses and the impeller because these parts of the filter are usually gentle and fragile. Before you reassemble the parts of the canister filter, it’s the best idea to ensure that every part is perfectly clean. If the cleaning you’ve performed is not complete, you can expect leaks.


What is the Best Canister Filter for Big Aquariums?

The canister filters listed here are great choices for your average fish tank but for larger aquariums, you may need to invest in something a bit more powerful. Like the FX6 Fluval Canister filter. It’s able to filter up to 563 gallons of water per hour! Perfect for aquariums up to 400 gallons. Here you can find the Fluval FX6 Aquarium Filter!

What’s the Best Canister Filter Media?

The best canister filter media we highly recommend is purigen, along with mechanical filtration and biological filtration of course. It does an excellent job at keeping your nitrate levels at 0ppm or close to it. It also keeps your water crystal clear and lasts several months!

How Do You Prime a Canister Filter?

The best way to prime a canister filter is by filling it with water before plugging it in. This way prevents the motor from overheating.

Canister Filters vs. Other Fish Tank Filters

As we have already mentioned, there are many different types of aquarium filters out there, so one might ask why they should choose canister filters over others. This is a legitimate question and the best part about it is that canister filters are not always the best choice. However, there are many situations in which these filters are more than useful.

Canister filters reign supreme in mechanical and chemical filtration. Regardless of the lack in biological filtration, canister filters are great for saltwater, freshwater tanks, for reef tanks, and turtle tanks. The compatibility of canister filters is what makes canister filters highly popular with many people.

Furthermore, you should take the price into consideration too. Canister filters belong to the group of aquarium filters that can be quite expensive like hob filters for example. They are also more expensive compared to all internal filters, but the truth is that internal filters are not very efficient. So, it is quite logical for a product that is very efficient and what it does like canister filters processing aquarium water to be expensive.

Taking care of a canister filter requires more time and effort compared to power filters, dry/wet filters, and under-gravel filters. So, unless you are prepared to follow the strict rules of maintenance associated with this type of filter, you should look for another solution.

You should also think about the size of the aquarium. There are canister filters designed to work in large aquariums and small aquariums. The same goes for the rest of the aquarium filters found on the market.

Conclusion: Canister Filters

Canister filters are one of the most popular types of aquarium filters today. They are extremely efficient, but only when they are maintained and used in the right way. A high-quality canister filter of this kind will provide the benefit of choosing the type of filtration adequate for your aquarium by letting you adjust the filter media. The other types of filters usually require the use of pre-designed and pre-made media. While it is true that canister filters require regular maintenance, the need for maintenance is much lower compared to power filters.

Keep in mind that when it comes to canister filters, just like when it comes to most aquarium filters, you must replace carbon in them regularly and frequently because the carbon – if saturated and not replaced after a long time can release the toxins it absorbs. Canister filters have proven to be excellent for medium and large tanks because they can process large amounts of water quickly. These filters provide excellent chemical and mechanical filtration and decent biological filtration.

When choosing a canister filter for your aquarium, look for products made by reputable companies. The models in this guide are used by thousands of people around the globe.

If you like the article above, here are some other similar articles you should check out!

Fluval Fx6 Canister Filter Review

Penn Plan Cascade 1000 Canister Filter Review

Best Aquarium Heaters – Buyer’s Guide


Hi, my name is Jordan. I've been in the fishkeeping hobby since my childhood. Welcome to my blog where I help fishkeepers enjoy the hobby by offering free guides, advice, & product reviews. Read more...

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