Fluval FX4 Canister Filter Review (2024 Complete Review)

Dr. Mollie Newton
Published by Dr. Mollie Newton PHD| Senior Editor
Last updated: July 13, 2024
Review Process and Evaluation Criteria
We conduct hands-on testing for all the products highlighted in our reviews and guides. Through anonymous product ordering and involving an independent team of testers, we gather direct experience to offer recommendations backed by data.

Explore the intricacies of the Fluval FX4 Canister Filter, a groundbreaking product cherished by aquarium enthusiasts! The Fluval FX4 holds a distinguished position among the top-tier canister filters on the market, celebrated for its exceptional functionality and superior filtration capability. If you’re considering buying this device and seek more information about its features, advantages, and possible disadvantages, you’ve come to the right place! We’re here to highlight its key characteristics, remarkable performance, and explain why it’s an essential addition to any aquarium.

Article Summary

  • The Fluval FX4 Canister Filter is highly regarded as one of the best canister filters on the market, offering superior performance and filtration for aquariums.
  • The filter is particularly beneficial for aquariums with large fish that have heavy bioloads, such as Oscar fish and plecos, due to its high flow rate and efficient filtration.
  • The alternative filter options, such as the MarineLand Magnum Polishing Internal Canister Filter and the AMOSIJOY 172GPH Canister Filter, are for those with different tank sizes and preferences.

Fluval FX4 Overview

Fluval FX4 Aquarium Filter

The Fluval FX4 is your answer to a clean, healthy aquatic environment. It has a Smart pump, large media baskets, multi-directional output nozzles, and compact design.

I’ve put together an extensive review of the Fluval FX4 so you can decide whether it’s the right filter for you and your aquarium. And, if you’re on the hunt for similar filters to this one, I also have you covered further down.

Things to Consider

The Fluval FX4 is a fairly big investment, so you definitely want to make sure it’s the right filtration device for your setup and needs before you part with your money.

Although it has a fairly high price tag compared to other canister filters, I do think it’s worth the cost as you can’t beat its performance in the long run.

This is a filtration device that will last you for many years, so you can rely on it to keep your fish tank clean longer than some lower quality, cheaper units.

Below are some things you may want to think to ensure this is the best filter for you and your fish!

Your Aquarium Size

The Fluval FX4 is designed for large aquariums that need ample filtration and flow, so if you have a relatively big setup, this filter is a great fit.

It has a pump output of 700 GPH (Gallons Per Hour), which the company claims is suitable for up to 250 gallons in volume. However, bear in mind that the filter itself has a flow rate of around 400 GPH, so I think it’s more suited for tanks up to 100 gallons in volume.

Nano tanks or those smaller than 100 gallons may not benefit from the Fluval FX4 due to its powerful filtration – it may be too strong for small fish, especially slow-moving species or those with long fins like the betta fish.

The Type of Fish In Your Aquarium

Due to its high flow rate and excellent filtration, the Fluval FX4 canister filter is particularly advantageous for large fish with heavy bioloads, such as Oscar fish and plecos.

It will have no trouble keeping the environment of big species healthy and clean.

That being said, this filter may not be the right choice for your fish tank if you have small fish or species that don’t make a lot of mess. It may be worth using a less powerful filter such as a sponge or power filtration system.

The Number of Fish In Your Aquarium

The last thing you need to consider before you purchase this canister filter for your tank is the number of fish you have in your aquarium. Due to the filter’s excellent filtration efficiency and high flow, it shines best when used in freshwater or saltwater aquariums with lots of fish.

You won’t get the most out of the filter if you only have a few fish in your tank. In addition, its flow rate may be too high for understocked aquariums.

Fluval FX4 Aquarium Filter

The Fluval FX4 canister filter offers fantastic filter circulation and efficiency so you can achieve a healthy, clean aquarium. Its advanced microchip technology continuously monitors its performance for optimal results. Better yet, its self-starting, comes with large media baskets filled with filter media, and is easy to use.

Fluval FX4 Aquarium Filter

Filtration devices play a crucial role in maintaining optimal water conditions in a fish tank. Fluval are well-known in the aquarium world for their high-quality products, particularly their filters, and the FX4 series is a powerhouse when it comes to superior filtration.

Boasting a multi-stage filter with multi-directional output nozzles that can pump out a whopping 700 GPH, it is one of the best filtration systems for large tanks that need ample filtration.

Smart Pump

It features a smart pump technology, which is not only self-starting, but also continuously monitors and optimizes pump performance for fantastic results each time.

Its self-priming feature makes it ultra easy to use – simply add water to the filter, plug it in, and the smart pump advanced microchip technology does all the work for you! After 12 hours of operation, the filter automatically evacuates trapped air to maintain its efficiency,

Unlike most canister filters, this one from Fluval sports a compact design (15.6” x 15.6” x 17.7”, so it easily fits under most aquariums!) and is relatively quiet during use, so it won’t take up too much space or emit a huge amount of noise.

Media Baskets

It has removable, stackable media baskets that can hold up to 1 gallon of filter media, the latter of which is included. This removes the need to lift heavy buckets for easy water changes. The device comes with everything you need to get it up and running in no time, including rubber feet, rim connectors, valve with drain hose, utility valve, drain cap pump unit, and a telescopic strainer.

While the Fluval FX4 canister filter is a great device, the main downside is that the filter itself is not rated for 700 GPH, like it claims. This flow rate is the pump itself – the actual filter has a flow of around 400 GPH.

Fluval FX4 FAQS

What Size Tank Is a Fluval FX4 For?

This filter is best used for aquariums up to 100 gallons in volume. Although the company states it’s suitable for tanks up to 250 GPH, the filter only has an output of approximately 400 US gallons per hour.

As a rule, your filter should be able turn over 4 times the volume of your tank per hour.

Is the Fluval FX4 Worth It?

Personally, I think this filter is worth it if you have a fairly large tank like a 75-gallon or 100-gallon as it provides excellent filtration, with the benefit of being easy to use.

Fluval FX4 aquarium filter pump

However, aquariums much smaller or bigger than this may not benefit from this filter. In the former case, it may be worth choosing a HOB, power, or sponge filter as canister filtration systems are best used for large setups.

If your tank is larger than 100 US gals, you may want to upgrade to the Fluval FX6, which is rated for 536 GPH compared to the FX4, which is around 400 GPH. Alternatively, you could use the Fluval 406, another excellent filtration device for big tanks.

Alternative Products

MarineLand Magnum Polishing Internal Canister Filter

The MarineLand Magnum Canister Filter is a great alternative to the Fluval FX series if you’re looking for something more affordable.

MarineLand Magnum Polishing Internal Canister Filter

Suitable for tanks up to 97 gallons, this internal canister filter from MarineLand will keep your aquarium crystal clear to make for simple water changes.

It has 2 refillable large baskets that you can store filter media in. It even comes with a polishing pad so you can achieve a sparkling setup. Bear in mind that this filter is internal, so you’ll need to place it inside your aquarium using the suction cups provided.

The main downside of this fish tank filter is its noisiness – the motor is quite loud, so it might not be the best choice if your tank is in your bedroom or living room.


  • Includes a polishing pad
  • Comes with large media baskets
  • Keeps your tank clean and sparkling

AMOSIJOY 172GPH Canister Filter

This filter from AMOSIJOY is a solid choice for aquarists that need a reliable and good-quality filtration device for a large tank.

AMOSIJOY 172GPH Canister Filter

The AMOSIJOY 172GPH Canister Filter boasts a lift-draw style valve and flow regulating handle, quiet operation, a high flow rate, and a large media basket. While it might not look as flashy as the Fluval FX4, it still matches it in performance and efficiency.

However, this device can be difficult to maintain as it’s pretty hard to clean, which may make it unsuitable for aquarists with limited time on their hands.


  • Quiet operation
  • Large media basket
  • Lift-draw style valve and flow regulating handle

SunSun HW-3000 UV 9W

The SunSun 5-Stage Filter offers excellent filtration, as well as an easy-to-read LED screen and self-priming feature. It even has an UV sterilizer built into it to eliminate algae and provide your fish with a healthy habitat.

SunSun HW-3000 UV 9W

Featuring 5-stage filtration, an adjustable flow, LED screen, UV sterilizer, and self-starting function, the SunSun 5-Stage Filter is a fantastic alternative to the Fluval FX4.

It’s just as powerful, high-quality, and comes with a few extra features that can really help you obtain a pristine, healthy aquatic ecosystem.

My only gripe with the unit is it can be a little noisy at times, especially on higher settings.


  • LED screen
  • Provides 5-stage filtration
  • Comes with a built-in UV sterilizer

Final Thoughts

I hope you enjoyed this review of the Fluval FX4 canister filter and were able to decide if it’s the right product for you and your fish!

What do you like the most about this filter, or are there other canister filters that you prefer? I’d love to hear what you think on our social media platforms. Be sure to share this post with fellow fish lovers too!

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