Aquarium Filters

Aquarium filters are undoubtedly one of the most important components of an aquarium. This is because filtration enables the tank to get rid of wastes and toxins that will become poison for your aquatic pets.

In this post, we’ll give you a list of some of the most popular brands of aquarium filters available. By the end of your read, you will hopefully have determined several great options for your pet.

But first, let us give you the basics.

How Do Aquarium Filters Work?

Unlike natural bodies of water, an aquarium is a closed system where waste and toxins build up quickly. This waste comes from fish poo, uneaten food particles, dead plant leaves, and other organic matter. To combat this, water changes are important.

Filters provide mechanical, biological, and chemical filtration to keep the water in the aquarium clean and conducive for aquatic pets. Filters do this by trapping debris, allowing the bacteria in them to break down toxins, and housing media that absorb dangerous chemicals. They also create flow and encourage oxygenation.

To be more specific:

  • Mechanical filtration is when the filter physically strains debris using a sponge, sock, wool, or any type of filter pad or cartridge. The finer or smaller holes these have, the more effective it can catch that debris.
  • Biological filtration is possible as that same filter media allow bacteria colonies to form on them while immersed in the tank water. These bacteria colonies break down ammonia (the byproduct of waste) and turn them into less harmful bacteria. This process is called nitrification.
  • Chemical filtration removes substances in the water that could change its composition (and thereby make it toxic to aquatic pets). Chemical filters include activated carbon and special resins that absorb substances like copper, chlorine, dissolved proteins, fertilizers, and medication.

Filters accomplish these types of filtration by running water through different types of filter media. This is not to say that water changes no longer need to be done when you have a filter. You still do, but just a lot less frequently. This makes aquarium maintenance so much easier.

Because they can get dirty and overwhelmed with absorbed substances, filter media should either be cleaned (like for sponges) or changed (like activated carbon) from time to time. The filter itself should be disassembled periodically and cleaned. You should know this because part of choosing the right filter is considering how to maintain it and its components.

The frequency of aquarium filter cleaning depends on how fast dirt builds up. If you have a large volume of water and a small bioload (few fish, low buildup of waste), cleaning becomes less often. Of course, there are variables, like how messy your pets are.

But all in all, having all these types of filtration working together will maintain your water parameters and keep the water fairly, if not crystal, clear.

A Comparison Of Different Kinds Of Filters

So now that we know how they work, we should also be aware that producers of these filters have different methods of achieving these. Thus, there are so many kinds of aquarium filters available. Some of the most frequently bought or built are:

Sponge filtersBiological, mechanicalEasy$
Box filtersBiological, mechanical, chemicalEasy√√$
Undergravel filtersBiological, mechanicalHard$$
Hang-on back (overhead) filtersBiological, mechanical, optional chemicalEasy√√$$
External canister filtersBiological, mechanical, chemicalHard√√√√$$$
Internal canister filtersBiological, mechanical, chemicalEasy√√-√√√$$-$$$
Overhead sumpsBiological, mechanical, chemicalEasy√√√√$$$
Wet/dry sumps (trickle filter)Biological, mechanical, chemicalAverage√√√  $$
Under sumpsBiological, mechanical, chemicalEasy√√√  $$

So you see there’s so much to choose from, the most common of which are sponge filters, hang-on back filters (which we fondly call HOBs), and internal canister filters. For the more experienced and serious aquarists with a bigger budget, canister filters and sumps (often custom-made) are used.

Experienced hobbyists usually customize their filters by changing the media. They also sometimes supplement their existing filtration by adding another machine.

A Review Of Popular Aquarium Filter Brands

Now let’s talk about some famous filter brands and how they are usually applied to the hobby.


Fluval has been around since 1975, maintaining a steady presence after introducing the world’s first 3-stage filtration device. They have a vast array of filters in the market today ranging from a nano to powerful external canister filters.

NameTypeTank SizeApplication Examples
NanoNano internal15 gallons maxNano tanks, small fish like a Betta, Shrimp
U SeriesInternal15 to 65 gallonsSmall fish like a Betta, Shrimp tank up to Turtle tank, community tank of medium-sized fish (Mollies, Rainbow Sharks, Danios, etc)
C SeriesHang-on-back30 to 70 gallonsSolo Betta or small school of small fish (Livebearers, Tetras, Rasboras) up to Turtle, group of Goldfish, community tank of small to medium-sized fish
07 SeriesExternal Canister10 to 100 gallonsSchool of small fish (Tetras, Minnows) up to Turtle, Cichlid community, single large Cichlid
FX SeriesExternal Canister250 to 400 gallonsTurtle, Cichlid community tank, Angelfish, Discus, group of Goldfish, large fish
G SeriesExternal Canister80 to 160 gallonsTurtle, school of Rainbow Sharks, Cichlids, Goldfish, community tank

What makes most Fluval filters versatile is their huge room for different filter media. Upon purchase, the box contains media for 3 kinds of filtration ranging from foams pads, to activated carbon, and ceramic rings. You can stick with these or add and change them depending on your preferences. Fluval also sells alternative media.


Another very popular brand in the hobby is Eheim mainly because of its efficiency and durability. Some people attest to using the same Eheim filter for decades and they’re still happy with it.

This company has been making aquarium filters for around 70 years. The variety of filters is astounding, with designs for the newbie up to the pond-keeper.

NameTypeTank SizeApplication Examples
Aquaball SeriesInternal15 to 47 gallonsSingle Betta to a sorority, school of Livebearers and smaller fish, pair of Convicts, a community of small fish
Classic SeriesExternal Canister40 to 300 gallonsSingle Betta up to Cichlid community for the 1500XL, Turtles
Ecco pro SeriesExternal Canister34 to 79 gallonsSchool of Livebearers, Rainbow Sharks, or Barbs, up to community tank, Turtle
Professionel SeriesExternal Canister105 to 184 gallonsCichlids, Goldfish, Turtles, large community tank
MODUL 4000Pond filter600 gallonsPonds of any size with Cichlids, Goldfish, monster fish

Reliable, easy to maintain— that’s what Eheim filters mean for many aquatic hobbyists. We especially love that the media baskets can hold so much, which means that customization is very easy.


For the more advanced aquarists— especially those in the saltwater aquarium hobby— CoralVue has almost everything you would need for your sump: fleece filters, pumps, valves, and protein skimmers to create your desired filtration system.

Originally a company that created diving lighting, CoralVue used its expertise in underwater electronics to develop saltwater filtration devices in cooperation with another company, Reef Octopus.

Today, CoralVue also has other sub-brands under its umbrella including Klir, AutoAqua, Aquaforest, and other saltwater aquarium specialists to name a few. These are great choices if you’re into taking care of Clownfish, saltwater Angelfish (like the Two-spined), Tangs, Gobies, Wrasses, and corals like polyps and trumpets.


Penn-Plax started as a pet store that gradually introduced its own products. From its founding in 1956 till now, the company uses its experience taking care of fish, reptiles, and amphibians to create effective aquarium products.

NameTypeTank SizeApplication Examples
Small World Under-Gravel Filter KitUnder-gravel filter3 gallonsNano tanks
Small World FilterInternal filter5 gallonsNano and fry tanks
 Cascade Nano-SpongeDouble sponge filter10 gallonsNano tanks, Shrimp, fry, Betta
BF1 Bubbler Bottom FilterBox/Bottom filter10 gallonsShrimp, fry, small fish like Bettas, Corydoras, nano tanks
Cascade Mini SeriesHang-on-back7 to 100 gallonsSmall tanks to Cichlid community tanks
Cascade Fully Submersible SeriesInternal canister10 to 50 gallonsNano tank to community tanks with small fish, small reef tanks for corals or pair of Clownfish
Cascade External SeriesExternal canister30 to 273 gallonsSchool of small fish to large reef tanks
Reptology OptimizerFilter optimizerBoosts capacity for any external canister filterLarge tanks for messy pets including Turtles, Frogs, Cichlids, Goldfish, reef fish and corals

We have included in this table Penn-Plax’s optimizer, which is not a filter per se, but a filter booster to be attached to any external canister. It’s perfect for anybody who wishes they have more space to house additional filter media. It’s not motorized, though, and will depend on the attached filter’s power for it to run.

Penn-Plax caters not just to aquatic pets, but to small mammals like cats, dogs, and rabbits as well.


AquaEL is a Polish company, and thus has the monopoly in the European market. This is also the reason why not all of its products are available on Amazon US or Canada. However, their bestseller, the ULTRAMAX, is a big hit among American hobbyists despite just being introduced a couple of years ago.

NameTypeTank SizeApplication Examples
Mini PlusInternal filter8 gallonsNano, fry, shrimp, tanks
MultikaniExternal canister20 to 85 gallonsNano tanks to community tanks, small reef tank
ULTRAMAXExternal canister80 to 185 gallonsCommunity tanks, reef tanks

What makes the ULTRAMAX unique is its inbuilt pre-filter system. While other brands offer you a separate pre-filter product, the ULTRAMAX has it by default. The additional system makes media cleaner for longer periods.

Users are very happy with the ULTRAMAX’s almost dead silent operation, ease of priming, and huge media baskets. But being from a different world region, the hoses aren’t standard sizes. But so far, so good for AquaEL.

Determining What’s Best For You

With all these types of filters in the market, it can get confusing. But remember that the best aquarium filter for your tank depends on what you need.

The main consideration when choosing an aquarium filter is how much filtration (or flow rate) you need based on how much bioload and water you have. Multiply that by 6 to 10 times and you have the flow or rate of gallons per hour (gph) you should buy.

For example, a planted 30-gallon tank with a school (around 6 fish) of Neon Tetras can have a filter with a 180 gph rating. Take the same tank and fill it with a school of messier or fast-reproducing fish like Guppies and you’d need a 240 to 300 gph-rated filter especially when the number of fish is multiplying rapidly.

If the filter doesn’t tell you how many gallons per hour it can turn, go for the lowest in its range to get the optimal result. This is also because the ratings that manufacturers put on the boxes work under perfect conditions, and you have to make allowances for that, more so if you have a particularly messy pet such as Turtles, Goldfishes, or Cichlids.

You can go for lower ratings if you have your bioload controlled. Having plants and lots of aeration definitely help, but do test your water often to be sure. For those who are just starting, you can take this as a general rule: if the box says the product is for a 30 to 60-gallon tank, use it for no more than a 30-gallon tank. Use a more powerful filter if you go beyond 30 (gallons).

Remember, it’s always better to have more power than you need than to be underpowered and struggle with keeping your tank water clean.

Tip: You can have more than 1 kind and type of filter if you have large tanks and/or sensitive fish. Many experienced hobbyists have a backup filter just in case the first one fails. The backup is usually the smaller one just to keep filtration running until the problem can be resolved.

Another tip on how you can further clamp down on costs is to never throw away the default filter media that you choose not to use. Save them as you never know when you’ll find them handy one day. Most of these are activated carbon-filled bags that aquarists choose to replace with additional bio or mechanical media. There are also sponges too coarse or too fine for some.

Recent Posts