Fluval 406 External Filter Review

We independently research our recommended products. We may receive commissions on purchases made from our links.

The Fluval 406 External Filter has its aim set for being the best Fluval filter around, and that’s saying something.

The company has made a reputation for innovation and is known for striving for improvements whenever possible. In the Fluval 406, this can be seen in not only keeping the good aspects of the earlier 405 model, but also by improving those parts due for an upgrade.

best fluval canister filter

The result is a filter with a large water capacity, plenty of filtration options and a decrease in generated noise.

One of the greatest joys in keeping fish is seeing your prized pets swimming around. Thanks to the Fluval 406, the water is so crystal clear you will be able to find your favourites in no time.

The filter itself works wonderfully well, and upkeep has been reduced to a minimum. For the times where you do need to change the filters, the system has been made both sturdier and easier to use, making the occasional cleanup a breeze.

Clean water makes for happy fish, and with the Fluval 406, it’s not hard to give your guppies a boost to their mood.

The only remaining question: is this the right filter for you? Have a look at the details and find out.

Fluval 406 External Filter: The Details


  • Weight: 10 pounds
  • Dimensions: 10 x 8 x 20 inches
  • Filter Capacity: 100 gallons/ 400 liters maximum, both fresh and salt water.
  • Flow Rate: 1450 L/H (383 US GPH)
  • Wattage : 120 V/60 Hz – 23 W
  • Media Stages: Mechanical, chemical and biological mediums, housed in separate modules
  • Self-Priming or Standard: Standard, but upgrades are possible
  • Warranty: 3-year limited warranty


The Fluval 406 comes with a variety of options and added accessories.

fluval external filter

Choose Your Medium
The multiple filtration baskets come ready to use with either mechanical, biological, or chemical filtering.

If you’ve never been a fan of one filter medium, you can easily swap it out for another. Make sure to read up on the needs of your fish, so you can make the best choice for their health.

Aqua-Stop Valve
The patented Aqua-Stop Valve makes upkeep something that can be done quickly and without too much hassle.

So no more cringing during maintenance or cleaning.

This is only aided by the single-motion lift-lock clasps that allow you to get into your filter with ease. These clasps are made stronger than in previous models so durability is ensured.

Designed for Silence

No longer will you be distracted by the whirring noises of your tank.

The sound-dampening impeller is added on this model ensuring the Fluval 406 runs as quietly as possible. Like the lock clasps, the impeller has also been redesigned in this model to be stronger than before.

This along with its cover and tight overall engineering will make those who are sensitive to noise a little bit happier.

Better Capacity and Durability
The unique square shape might not seem impressive at first, but it has increased the capacity without compromising on other aspects.

So you’ll be able to hold more, without sacrificing the look and size of the filter.

Speaking of looks, the design is sleek and built strong. The outside and the inside of the machine have been made from durable materials instead of cheap flimsy plastic that can be seen on subpar filters.

This means that with a little care, this filter could give you years of service.

Instant Priming System

The filter comes with an instant priming system so you don’t have to be left with the task of manual siphoning or mouthfuls of tank water.

This makes start-up quicker and easier, especially for newbies.

Fluval 406 External Filter Review

The Positives

Efficient Shape

Thanks to its unusual shape, the Fluval 406 External Filter has a capacity ranging between 35% and 40% higher than most of the other filters out there.

This means space for more water to be filtered, as well as less wasted space on the inside of the filter.


Fluval wants you to feel secure by including a three year limited warranty. This beats out the usual 30 days to a few months of coverage offered by other companies.

Should there be any manufacturing defects or flaws on their behalf, Fluval will accept the return of your filter for a repair or replacement.

Just be careful not to damage or harm the product yourself and Fluval should have you totally covered.

Sturdy Design

The material used to make this filter was meant to last, and it shows from the moment you take the Fluval 406 in your hands.

Everything from the caps and valve down to the filter modules promises to last you a long time.

This combined with it’s extended warranty means no fussing with replacements any time soon.

Versatile Modules

The Fluval 406’s main selling point is how clean it keeps your water. It does this with the aid of several cleaning modules, allowing you to take your pick from mechanical, biological, and chemical filters.

The media baskets come in different sizes, meaning you can mix and match according to the needs of your aquarium.

The inside of the filter has been made so that every bit is used to filter water and get the muck out, leaving your fish to enjoy their beautiful clean water.

best cheap canister filter

Easy Set-Up

Beginners don’t have to worry thanks to the ease of the Fluval 406 filter.

This filter is super easy and quick to set-up and also includes an easy to follow manual to walk you through the initial set-up.

Simply decide where your hoses need to go, put the media and baskets into the canister, hit that primer and voila. Easy as pie.

Easy Cleaning

Apart from being the best canister filter on the market, the Fluval 406 is also one of the easiest to clean.

How often this needs to happen depends on the variety of fish you’re keeping, but this filter makes the task itself a cinch.

The Aqua-Stop Valve and the one-motion clasps mean opening and closing the filter is a breeze, and the filter media themselves are just as easy to operate.

For those who are still insecure about their skills, remember there’s a guide included with the filter, so no need to panic.

Here’s a video showing one way of cleaning the Fluval 406 Canister Filter.

Adjustable Capacity

Sure, the maximum capacity of this machine is pretty impressive, but that doesn’t mean you actually have to use it. Thanks to the different filter mediums, it’s easy to adjust according to your needs.

If you have a rather small tank now, having the Fluval 406 around means that when you decide to upgrade, you already have a matching filter.

Sound-dampening Impeller

Having fish around is a great sight for sore eyes, but sometimes the sound of the filter lessens the pleasure.

With the new sound-dampening impeller, the Fluval 406 is up to 15% quieter.

Say goodbye to the days where you can practically hear the filter screeching through the dirty water, and enjoy watching your pets in peace and quiet.

Strong Flow

Not only is this filter quiet, and durable, it’s also powerful.

You can expect to get a steady strong flow from the start with the Fluval 406.

Keep in mind the flow rate is adjustable so if you prefer a softer flow, it can be done easily.

The Negatives

Spray Bar Not Included

For some people, not having a spray bar is not a big deal. If your fish are more delicate, a spray bar does mean the difference between a happy fish and an unhappy one.

Luckily it’s easy to attach a spray bar to the filter; just keep in mind that you’ll need to buy it separately.

Inconvenient Rubber Hose

The overall design of the filter is sturdy and classy, while still being able to use with ease. The one part that seems neglected is the rubber hose.

It’s the part of your filter most likely to clog up, so being able to easily see what’s happening would have been nice. It’s also rather hard to connect to accessories like water heaters.

Easy Cleaning, But…

If you’re new to keeping fish, you’re probably not very experienced with cleaning a filter.

Though this isn’t much of a problem with the Fluval 406, it’s easy to mess up closing your caps properly. And seeing how strong this filter is, that might mean a few litres of water on the floor before you realize your mistake.

Just another thing to keep in mind for beginners.

Doesn’t Hang On Back

If you’re used to HOB (hang on back) filters then the Fluval 406 might be a whole new world for you.

It’s an external canister filter that is meant to sit above, below, or next to your tank or to be tucked away. This means that if you expect to hang it off your aquarium, you’ll be out of luck.

With no clasps, or hooks to accommodate hanging, you’ll probably have to get crafty to keep it attached to your tank.

Not a deal breaker but something to be aware of before purchasing.

fluval external filter

Overall Verdict

The Fluval 406 is a workhorse. It offers an exceptional filter capacity, and thanks to its heavy-duty nature, will ensure your water is pure and clean with very little input from you.

This helps you feel confident in the aesthetics of your tank as well as the health of your fish. Thanks to its versatility, this filter can be used for both low-maintenance aquariums as well as more demanding species.

However, the filter has a few beauty problems and may lead to some messy – watery – mistakes. When it comes to fully ensuring the safety of your fish, you may have to make an additional investment in buying extra features.

Yet, all in all, even for beginners, the Fluval 406 External Filter is a one-stop-shop kind of filter that will deliver quality for years at a time.

Where to Buy the Fluval 406 External Filter

Fluval is a popular, well-known brand when it comes to filters and their products can be easily found in local stores or online. The powerful Fluval 406 has become just as popular making it easy to find for purchase.

To start, check out the following online retailers:

And of course, it’s also available for purchase on Amazon.

fluval external filter

That wraps up our review for the Fluval 406 External Filter. Curious to give it a try?

Fluval 406 External Filter Rated
  • Quality of Filtration
  • Build Quality
  • Accessories
  • Ease of Use
  • Value for Money

FCG Verdict

The Fluval 406 External Filter is a great option for beginners as well as professionals.

It’s space, sturdy design, and power will ensure that your pets will have crystal clear water for a very long time.

The Fluval 406′ performance shines through its small hiccups and is followed by an attractive price tag.

>>> Check today’s price on Amazon.

Leave a Comment