The 9 Best Aquarium Canister Filters

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This wiki has been updated 17 times since it was first published in June of 2018. If you were to stop removing debris and toxins from your aquarium, it would become uninhabitable for your aquatic friends in no time. With one of the dependable canister filters featured here, however, you can keep the environment for your fish and plants safe and sparkling clean. Our selection includes designs to accommodate a wide variety of tank capacities and budgets. When users buy our independently chosen editorial choices, we may earn commissions to help fund the Wiki.

1. Fluval FX-6

2. Eheim Classic External

3. Oase Biomaster Thermo

Editor's Notes

December 17, 2020:

The Oase Biomaster Thermo joins the list in this update, and it’s a versatile choice that also functions as a heater, so you can keep the heating element out of your fish tank, leaving more room for aesthetic elements like plants and lights, not to mention your fish. It also supplies biological, mechanical, and chemical filtration. It’s available in three sizes, features a handle that makes for easy lifting, and operates in nearly a silent manner. We also changed the Fluval 306 to the updated Fluval 307, a similar design that features an efficient priming system and can move up to 303 gallons per hour. Made to be quieter than its predecessor, this updated model incorporates a sound-dampening impeller.

The powerful Fluval FX-6 retains a prominent spot on the list, and works with aquariums of up to 400 gallons. You conveniently can stack the media in whatever combination of layers you desire, thanks to its set of media baskets with foam inserts. It provides handy automatic maintenance reminders and boasts a reliable self-starting mechanism. We’re also still partial to the Eheim Classic External, which isn’t likely to suffer troublesome leaks, since it’s equipped with a tight-fitting silicone ring situated on the pump head. It’s appropriate for either saltwater or freshwater use and you won’t need to worry about it using up a lot of energy. The Penn Plax Cascade 1500 is a good choice that makes it easy to situate your preferred media on the equipped stackable trays and valves to control the flow rate. If you’re concerned about a filter disturbing your fish, consider the Hydor Professional External 600, which produces minimal vibrations or noise. You can conveniently have it up and running in a matter of minutes, and helpful setup videos are available online.

July 10, 2019:

An aquarium filter is a must when it comes to clearing waste products and other toxins from your fish’s water, as well as supplying the fresh oxygen your scaly friends need for survival. Canister filters are are known for their power, and they’re generally for use with aquariums that have a capacity of at least 40 gallons. They’re made to operate outside the tank, which is most cases is preferable, since they can easily be hidden in the cabinet underneath your aquarium. When choosing the right one for you, make sure it’s designed to handle the capacity of your fish tank. Also pay attention to a given model’s gallon-per-hour (GPH) rating. An appropriate minimum turnover rate for your tank would be four times the capacity of the tank per hour. For a 40-gallon tank, for instance, the GPH should be around 160.

All of the models in our selection have a listed GPH rating, and some come with filtration media to get you started. Joining the list today is the Cobalt Aquatics 26000, which is known best for its versatility, as it can be placed just as easily above, below, and next to your tank. It comes in at a budget-friendly price, and you can buy it with confidence, thanks to its generous three-year warranty. Unlike some others, it can be used with any brand of filtration media, which can save you even more money over time. It’s from an aquatic products company founded in 2011 by three self-proclaimed “fishgeeks,” including a former biologist and an importer of African cichlids.

The Fluval FX-6 moved up on the list in this update, as a reliable, tried-and-true choice that features a self-starting design, so you’ll need to do little more than adding water and plugging it in. It’s for larger aquariums up to 400 gallons in capacity, and works in either freshwater or saltwater environments. Its powerful motor is located in the lid, and it’ll move a lot of water and keep the inside of your tank sparkling clean. This durable model has a reputation for lasting for years.

A smart choice for those with a smaller tank (it’s made for those up to 95 gallons) is the Eheim Classic External, our #2 choice. It’s equipped with a permo-elastic silicone sealing ring to make sure it doesn’t leak, and with it, you’ll get an array of filter media like surface area biomedia, a sponge, a carbon filter floss, and a polishing pad. It weighs just 14 pounds and is also compact in size, so it’s easy to place in the cabinet under your aquarium.

4. Penn Plax Cascade 1500

5. Fluval 307

6. Hydor Professional External 600

7. Cobalt Aquatics 26000

8. MarineLand Magniflow 360

9. Aquatop CF Series 525

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Karen Bennett
Last updated by Karen Bennett

Karen Bennett lives in Chicago with her family, and when she’s not writing, she can usually be found practicing yoga or cheering on her kids at soccer games. She holds a master’s degree in journalism and a bachelor’s in English, and her writing has been published in various local newspapers, as well as “The Cheat Sheet,” “Illinois Legal Times,” and “USA Today.” She has also written search engine news page headlines and worked as a product manager for a digital marketing company. Her expertise is in literature, nonfiction, textbooks, home products, kids' games and toys, hardware, teaching accessories, and art materials.

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