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Which Is The Best Internal Fish Tank Filter And Why? Read All About It!

Aquariums are nice décor, while you’ve bought the house. Sadly, the equipment themselves could make house administration harder, particularly filters.

Whether or not they’re hanging on the again or working a ton of tubes into the tank, exterior filters want numerous house. However, inside filters don’t.

One of the best inside fish tank filter will sit completely inside your tank. You possibly can shove that tank proper as much as the sting of the wall with out leaving 6 inches on all aspect for the needy filter.

Study extra about inside filters, how to decide on a very good one, and see our opinions of some of our favorites…

8 High-Rated Inner Fish Tank Filters To Purchase In 2022

1 Aqueon Quietflow Inner Energy Filter

There are 4 completely different sizes obtainable for this filter. It is available in 10, 15, 30, and 40-gallon fashions. Every mannequin has slight measurement variations based mostly on the circulate charge.

Aqueon’s Quietflow inside energy filter is a totally submersible filter that sits wherever within the tank. Place it vertically or horizontally, so long as it’s absolutely underwater. It shouldn’t keep on whereas out of water.

This filter has all 3 phases of filtration. It makes use of cartridges which can be replaceable and straightforward to seek out. As soon as you understand the cartridge measurement, which can change between filter sizes, you should buy any cartridge with comparable dimensions.

Change the route of the water return valve if the circulate charge is messing together with your tank. It may be shortened, lengthened, and re-directed as wanted. Circulate charge may also be adjusted decrease if it’s too sturdy in your fish.


If all you want is a straightforward inside filter in a small to medium tank, you’ll most likely be proud of this Aqueon mannequin. It doesn’t have any bells or whistles or advanced options to fret about, making it a fast, simple resolution for clear water.

Need the total image? Let’s spill the tea…

Aqueon Quietflow Internal Power Filter
Our rating:3.6 out of 5 stars (3.6 / 5)

  • Unobtrusive design seems to be nice in most tanks
  • Included suction cups work effectively
  • Small measurement makes it inconspicuous
  • Rotating water return head helps out in smaller tanks
  • Runs quietly with solely barely audible noise
  • 4 completely different buying choices
  • Cartridges included in equipment aren’t excellent, you could want to purchase your personal
  • Circulate charge adjustment nob is troublesome to make use of
  • Tank measurement suggestions could also be overrated for bigger sizes

2 Penn Plax Cascade 300

The Penn Plax Cascade 300 is a totally submersible inside filter with a clear blue backside part and a black prime. It’s obtainable in packs with 1 to five full filters per pack.

This filter’s circulate charge is 70 GPH. It’s meant for tanks round 10 to fifteen gallons in measurement. You possibly can place it wherever in your tank, horizontally or vertically, so long as it’s largely submersed. The circulate charge is adjustable.

Fairly than utilizing cartridges, this filter has a excessive capability filtration media cup that accepts free media. You possibly can fill it with no matter you need and get the fitting degree of filtration in your tank. It really works effectively with sponges and most organic and chemical filtration media.

For the output, you possibly can have the highest water output spout hanging above the water for aeration. Or, you possibly can place it under the water to evenly distribute the water. Water output doesn’t create any undesired currents within the tank.


This submersible filter offers you extra choices for filtration media. It’s a good selection if you would like extra flexibility as a substitute of utilizing solely particular cartridges. The circulate charge can be sturdy sufficient to do effectively in small tanks with out struggling.

Have a look at the professionals and cons of this filter…

  • Massive house to place free filtration media of your selection
  • Simple so as to add additional aeration with water output return spout
  • Could be appropriate with cartridges
  • Excessive circulate charge for a small filter measurement
  • Helpful in freshwater and saltwater tanks
  • Suitable with hoses for equipment powered by the output pump
  • Comprises a pre-filter
  • Easy to open and clear
  • Weak suction cups
  • Creates some vibrations that may hassle your fish, could also be barely audible outdoors the tank
  • Pre-filter can clog rapidly, requires common cleansing

3 Marina I25 Inner Filter

The Marina I25 filter is a small, black clip-on filter for tanks as much as 6.6 gallons. It’s a very good various for small tanks that don’t have numerous house for filtration. The GPH is a most of 26.4.

Whereas that is an inside filter, it should sit vertically. You can not place it horizontally, due to the inside water circulate system. Water is available in by the underside and trickles out from the highest.

A cartridge sits within the heart of the filter. Every filter accommodates mechanical, organic, and chemical filtration. Water enters within the heart of the cartridge, giving it extra time to work together with a lot of the media inside earlier than it trickles again into the tank.


For those who’re in search of a easy vertical filter in your tank, this can be a good small choice for many little tanks. It doesn’t take up a lot house and appears discreet within the tank.

Right here’s a extra holistic take a look at it…

  • Nice for small and really small tanks
  • Very efficient filtration
  • Good for betta tanks
  • Mild circulate again in to the tank, doesn’t disturb your fish
  • Good filtration media capability for small tanks
  • Motor sits underwater, masking any noise
  • Should be positioned vertically
  • Could also be too tall for some tanks
  • Tough to take away cartridge for cleansing

4 AquaTop Inner Filter

A filter meant for small to medium tanks, this filter is accessible for tanks as much as 10, 20, 30, or 40 gallons. The circulate charge of every filter matches the utmost tank score, with the smallest beginning at 42 GPH.

AquaTop’s inside filter doesn’t take up numerous house. It’s additionally vitality environment friendly, with the smallest mannequin working on solely 2.5W of energy.

This can be a sponge filter. Inside, there are not any cartridges or different forms of filtration media, solely sponge filtration. You need to use a smaller sponge and embrace organic media, if desired. Nonetheless, the sponge may additionally act as a bio filter over time if used solely with tank water.

The filter is absolutely submersible. Place it wherever throughout the tank. Water returns to the tank by the spray bar, which will be submerged or above the water line for added aeration.


For simplicity, this can be a nice selection. Upkeep is simple, and the filter is straightforward even for freshmen to arrange and use.

Let’s check out it from either side…

AquaTop Internal Filter
Our rating:3.5 out of 5 stars (3.5 / 5)

  • Good for betta tanks
  • Effectively-balanced circulate charge for many fish
  • Circulate charge is adjustable on all mannequin sizes
  • Consumption doesn’t hassle betta fins
  • Small measurement is simple to suit into your tank
  • Added aeration from water output
  • Solely mechanical filtration included, no organic or chemical filtration
  • Some audible noise
  • Small sponge will get soiled rapidly
  • Constructed-in suction cups aren’t sturdy

5 Fluval Underwater Filter

There are 4 completely different measurement fashions of the Fluval underwater filter. They’re as much as 15 gallons, 12-30 gallons, 24-40 gallons, and 34-65 gallons.

This can be a absolutely submersible filter. Place it vertically or horizontally wherever within the tank. Water sucks in by a backside consumption nozzle and returns to the tank from a multi-directional output valve.

Use cartridges for filtration on this Fluval. There may be house for one or two cartridges, relying on the scale of filter you get, and a few free media reminiscent of sponges and charcoal filtration. All preliminary filtration media is included within the equipment while you buy it.

Circulate charge is adjustable for all measurement fashions. It attaches to the glass within the tank with built-in suction cups.


For a easy filtration choice that works in numerous completely different tank sizes, this can be a good selection. It’s bought a various filtration media setup to offer you slightly extra customization. Think about this the submersible cousin to the favored Fluval 406 filter.

Right here’s extra on the total story…

Fluval Underwater Filter
Our rating:3.5 out of 5 stars (3.5 / 5)

  • Runs quietly
  • Versatile filtration media decisions
  • Mild present gained’t disturb your tank
  • Compact measurement is simple to rearrange within the tank
  • Water will be returned to the tank by a built-in spray bar
  • Attaches to the tank with a suctioned bracket, so that you don’t need to take away suction each time
  • Good for small turtle tanks in addition to fish
  • Circulate charge is troublesome to regulate
  • Free media part is sort of small
  • Grime can fall out of the filter while you take away it from the tank
  • Might not work effectively for rated tank sizes

6 Penn Plax Cascade 600

For tanks from 20 to 50 gallons in measurement, the Penn Plax Cascade 600 is an efficient selection. It’s a blue and black filter with a clear media chamber.

This can be a absolutely submersible filter that may be positioned wherever within the tank. Water is available in by an consumption valve straight into the media chamber. The chamber is customizable, together with for free media.

You possibly can select to return the water to the tank by the naked output valve or a sprig bar. Water will be redirected to decrease the impression of the return present. Circulate charge can be adjustable.

Use any sort of media that matches into the chamber. Sponges and free media of every type are appropriate with this filter. Some filtration media is included to get you began.


If you need extra choices in filtration media with out shifting to exterior filtration, this can be a good choice.

Is all of it excellent news? Learn on…

Penn Plax Cascade 600
Our rating:3.7 out of 5 stars (3.7 / 5)

  • Massive filtration media capability
  • Non-obligatory spray bar return
  • As much as 175 GPH circulate charge
  • Impeller will be eliminated individually for cleansing or alternative
  • Totally customizable filtration media setup
  • Runs very quietly
  • Works effectively for small turtle tanks
  • Tough to open the highest carbon filter field
  • Filter design might not be protected for small to medium-sized snails, shrimp, and small fry
  • Might have frequent upkeep
  • Included sponge media distorts in form and clogs simply

7 Tetra Whisper In-Tank Filter

The Tetra Whisper In-Tank Filter is available in 5 completely different measurement choices: as much as 3, 4, 10, 20, or 40 gallons. Every mannequin has the identical primary design with completely different sizes relying on the gallon score.

Filtration media cartridges are laid out vertically for straightforward entry. You possibly can simply attain them to alter cartridges or clear them. Cartridges can be found for alternative.

This can be a partially submersible filter. Don’t submerge it absolutely underwater. Place it vertically with solely the underside half within the water. The whole filter matches neatly into the tank with none elements hanging externally.


For all types of tanks, nor simply fish tanks, this filter offers you slightly little bit of flexibility. The addition of an air pump makes it good for tanks that want extra oxygen.

What else ought to you understand?

Tetra Whisper In-Tank Filter
Our rating:3.7 out of 5 stars (3.7 / 5)

  • Impeller is definitely accessible for cleansing
  • Good for turtle tanks and terrariums in addition to aquariums
  • Consists of air pump for higher aeration
  • Mounts on brackets or with suction cups
  • Most tank measurement scores are pretty correct
  • Creates a waterfall impact into the tank
  • Might not slot in all smaller tanks, because it’s not absolutely submersible
  • Can not sit horizontally
  • Some audible noise
  • Smaller sizes clip on, which can not work in all tanks

8 MarineLand Magnum Sprucing Inner Filter

You should purchase the MarineLand Magnum sharpening inside filter in a pack of 1, 2, 3, or 4 filters without delay. Every filter is similar measurement and works on tanks as much as 97 gallons in measurement. The utmost circulate charge is round 290 GPH for this filter.

As a canister, it has contained filtration media inside. The distinctive inside setup makes use of a sequence of sponges, media cartridges, and different elements to carry out all 3 forms of filtration. There are 2 media chambers which can be customizable.

As a result of it’s absolutely submersible, no priming is critical. This can be a watertight unit that may be positioned wherever throughout the tank with out fear.

A further water sharpening choice makes water clearer. It removes advantageous mud particles and tiny particles from the water, leaving it a lot clearer and fewer foggy general.


If you want a submersible filter in a big tank, you don’t have numerous choices. The MarineLand Magnum offers you a very good choice for medium to giant aquariums as a substitute of simply smaller tanks.

Is it value it? You resolve…

MarineLand Magnum Polishing Internal Filter
Our rating:3.8 out of 5 stars (3.8 / 5)

  • Highly effective sufficient for giant tanks
  • Totally submersible for versatile placement
  • Simple to open up and clear
  • Works effectively to clear up water
  • Nice customer support from MarineLand if there is a matter
  • Runs quietly underwater
  • No priming vital
  • Present from returning water is robust
  • Impeller design could also be liable to breaking over time
  • Mechanical filtration clogs simply
  • Pump can vibrate the filter and trigger noise over time

What To Look For In An Inner Tank Filter

Inner filters sit underwater, totally contained in the tank. Due to this distinctive setup, there are a couple of additional issues so that you can take note of while you’re shopping for one. Right here’s are the principle issues that matter for an inside filter:

  • Circulate Charge

Relying on the scale of your tank, you’ll want a sure circulate charge. Bigger tanks want stronger circulate charges whereas smaller tanks can get by with decrease circulate charges. It’s troublesome to overpower a tank, although it’s doable in the event you get a filter that’s rated for a lot bigger tanks.

Typically, the circulate charge of the filter must be 3 to 4 occasions the variety of gallons within the tank. Circulate charges are measured in gallons per hour (GPH). Because of this all of the water within the tank can undergo the filter not less than 3 occasions per hour.

Fish Tank Filter 1

Inner filters are sometimes small and have decrease circulate charges. That is advantageous, so long as you don’t attempt to use them for bigger tanks. You possibly can put a number of inside filters in the identical tank to enhance the circulate charge.

Tanks which can be absolutely stocked or overstocked want extra filtration energy. You probably have messier fish, like goldfish, you additionally want a stronger filter.

  • Totally Or Partially Submersible

Not all inside filters are absolutely submersible. Take note of this. It impacts the way you’ll set up the filter and the place it goes within the tank.

Partially submersible filters can’t go on the underside of the tank, except it’s a shallow turtle tank. Totally submersible filters go wherever, however they need to all the time be coated with water. Select the inner filter sort that most accurately fits your tank.

  • Filtration Media Sorts

Smaller filters could restrict the forms of media you possibly can add contained in the filter. You desire a filter that may do mechanical, organic, and chemical filtration. Even small tanks profit from this mix.

Fish Tank Filter 2

Most inside filters use cartridge filtration media. Cartridges are handy, however they restrict what you need to use and the way a lot of every sort of media you possibly can have. If it makes use of cartridges, ensure the obtainable cartridges cowl your wants.

  • Filter Type

Not all inside filters look or function the identical manner. Some stick onto the tank glass close to the highest of the water whereas others can lay horizontally on the underside of the tank. Discover a form and magnificence you want in your tank, small or giant.

  • Upkeep

Do not forget that you must clear and re-stock your filter to maintain it working at its peak. Easy upkeep is a blessing. Get a filter that’s as simple to wash as doable.


You’ve bought choices. Inner filters aren’t only for tiny tanks. You will get one thing just like the Aqueon Quietflow Inner Energy Filter for smaller tanks, or get the MarineLand Magnum for a big tank.

Match your filter to your tank’s filtration wants. Do not forget that capability and filtration kinds are the massive factors of comparability. Don’t short-change your tank. Get what your fish want!

2 thoughts on “Which Is The Best Internal Fish Tank Filter And Why? Read All About It!”

  1. I have had no luck with Aqueon filters of late. Both the internal and HOB are dying en mass and are less than half a year old. With regular maintenance these used to last forever but the new models are made of inferior quality/less durable parts. I have had fish for almost 20 years and won’t buy another Aqueon anything!

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