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4 Best Internal Aquarium Filters 2020 (Detailed Reviews)

If you are looking for the best internal aquarium filter then you are at the right place. In this article, I have reviewed the best internal filters available in the market. 

List of the best internal filters for aquarium 2019 (Detailed Review)

I recommend Penn Plax Cascade Submersible Aquarium Filter. It is a pretty effective filter and it comes with additional accessories. Also, it comes with all the adjustments so you can customize it according to your needs. Check its latest price and customer reviews at Amazon here

ImageNameTank SizePrice
Whisper In-Tank Filter with BioScrubber for aquariums
Up to 3, 10, 20, 40 gallons

Check the latest price at Amazon here

Aqueon Quietflow Internal Power Filter
Up to 10, 15, 30, 40 gallons

Check the latest price at Amazon here

Penn Plax Cascade Submersible Aquarium FilterUp to 10, 20, 50 gallons

Check the latest price at Amazon here

Marina I25 Internal FilterUp to 6.6 gallons

Check the latest price at Amazon here

1. Tetra Whisper in-Tank Filter with BioScrubber

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This filter has quite a few variants and some of their specifications vary. This filter comes in a total of 5 variants.

Here I’m going to review the “upto 10-gallon” variant.

Obviously, this filter can be used for tank upto 10 gallons. It uses a medium Bio-bag filter cartridge for filtration. 

It comes with a hanger so you can hang it inside the tank. It also comes with suction cups so you can also put it into one of the back corners where it will not be visible with the help of suction cup.

It is quite large in size so it will take a lot of real estate of your tank. 

The motor of this filter is submerged in water that’s why it is very quiet.

This filter can work in 2-3 inches of water which makes it ideal for turtle tanks. It will also create a nice little waterfall. 

This filter also comes with a pre-assembled Bio-bag cartridge so you don’t have to buy a separate cartridge for it.

This filter comes with bio scrub. If the Bio-scrub gets dirty then you can simply rinse it and put it back in the filter. 

If you want to replace the Bio-screen once it gets dirty, you can easily find one at your nearest pet store or Amazon also has some here.

If you have a rim on your water tank them you will not be able to hang it on the wall of the tank because the hanger clip of this filter is very tiny and it will only fit in on the rimless water tank. 

You can put it inside one of the back corners or at the bottom of the tank.

The length of the cable for wall connection is about 6 ft.

Overall it is a decent filter but it lacks many features that its competitor offers like water flow adjustment, height adjustment, etc.

Pros

  • Quiet
  • Easy maintenance

Cons

  • Big size
  • No adjustments

Price

Check latest price and customer reviews at Amazon here

2. Aqueon Quietflow Internal Power Filter

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Aqueon Quietflow is a very small and compact internal filter. It will not take much real estate of your tank which makes it ideal for small tanks upto 10 gallons. 

It is a fully submersible internal filter and it comes with four suction cups to mount on the wall or on the base of the tank. You can use it horizontally or vertically in your tank.

It uses Aqueon replacement filter cartridge and it comes with three-stage filtration:

  1. Mechanical filtration
  2. Chemical filtration
  3. Biological filtration

The first stage of filtration is consist of dense foam to remove particles and debris. The second stage of filtration has activated carbon to remove toxins, odors, and discoloration. And the third stage has patented Biogrid for ammonia and nitrates. 

This is a pretty adjustable filter, you can adjust the water flow rate but some users found it hard to adjust the water of it and also the water flow rate is high even at the lowest setting. 

To adjust the water flow remove the extension tube and twist it. You can set it to high, medium and low. For example, twist it all the way to the right to maximize the water flow and vice versa.

You can adjust the height and direction of the filtered water as well. 

Overall Aqueon Quietflow is a very compact filter, it is highly adjustable and it comes with three-stage filtration.

Pros

  • Adjustable water flow
  • Adjustable filtered water direction
  • Adjustable filtered water height
  • Compact
  • Fully submersible

Cons

  • High water flow at low setting as well
  • Hard to adjust the water flow

Price

Check latest price and customer reviews at Amazon here

3. Penn Plax Cascade Submersible Aquarium Filter

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If you are looking for a feature-packed internal filter then Penn Plax Cascade 300 internal filter is ideal for you. 

I am saying it is a feature-packed internal filter on purpose because it has literally all the features and internal filter can have from directional water flow to a connector to supplement your accessories like fountains.

This internal filter is ideal for a 1.5-gallon aquarium to 10-gallon aquariums and terrariums.

It is a fully submersible internal filter which makes it very quiet. 

You can easily amount it horizontally or vertically according to your needs with the help of its suction cups.

This can pump 70 gallons of water per hour for your marine or fresh aquarium.

And it comes with three-stage filtration that is biological, chemical and physical.

It also comes with activated carbon cartridge which filters out harmful chemicals, toxins, and odors. 

Also, it helps in discoloration and removes other harmful contaminants from your aquarium.

It comes with an internal sponge which optimizes the colonization of beneficial aerobic bacteria.

The bio sponges and the filter cartridge of this internal filter is replaceable.

You can also replace the foam with any other biological media like ceramic if you will.

The capacity of the filter cup is large so you can virtually add any type of media you want.

The return water flow of this filter adjustable so you can direct it in the direction you want using its directional nozzle.

The nozzle also has a connector so you can connect to any kind of accessories like fountains with the help of flexible tubing.

This internal filter comes with a spray bar as well which basically allows you to distribute the water evenly on the surface of the tank water which also helps in aerating the water.

This option is good for dedicate fishes that do not want high water flow like Betty and Angels.

It also comes with a flow controller to adjust the flow of the water according to your needs.

It also has Venturi aeration which is a tube you can attach to the filter when it is fully submerged in the water and the other end of the tube will be outside of the tank which helps to oxygenate the filtered water, saving you money for an air pump (I told you it is a feature pack internal filter).

Although it is a fully submersible filter it is not as quiet as you expect it to be, you can hear hums.

Overall this is all in one internal filter which comes with a directional nozzle to direct the water flow. 

The nozzle also has a connector to connect to your accessories like a fountain.

A spray bar to distribute the water flow evenly around the surface of the tank water. 

Venturi aeration to oxygenate the filtered water

Flow controller to regulate the floor of the filtered water.

Pros

  • Adjustable water flow
  • Adjustable filtered water direction
  • Nozzle to connect accessories
  • Comes with spray bar
  • Fully submersible
  • Comes with Venturi aeration

Cons

  • Not very quiet

Price

Check latest price and customer reviews at Amazon here

4. Marina i25 internal filter

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If you are looking for an internal filter for your small aquarium up to 6.6 gallons then Marina i25 internal filter is a good choice for you.

This is a very small and compact filter perfect for your small aquarium.

It reduces the odor and pollutants from the tank with an effective mechanical, chemical and biological filtration process.

Firstly the water enters into the zeolite chamber where the toxic ammonia is removed. Then it enters the second chamber which contains carbon, it removes odor and pollutants from the water.

After that, the floating debris gets trapped in the cartridge making the water crystal clear.

How often you will have to change its filter will depend upon how dirty your tank gates i.e. how many fish your tank contains usually you will have to change the filter after every 3 to 4 weeks.

As the motor of this filter is submerged in the water, it is very quiet too.

It comes with only one power cartridge.

It keeps the water clean and aerated.

You cannot keep it horizontally you have to keep it vertically inside the aquarium.

It has a pin clip to hang it on the wall of the tank from inside and it also comes with 2 suction cups.

If you have a lid on the tank then you may not be able to put on the lid on the tank after hanging it on the wall of the tank.

In this case, you can also mount it using its two suction cups on the wall of the tank but you will have to make sure the filter is not fully submerged in the tank.

The power cord of this filter is around 6 feet long.

It filters about 26 gallons per hour.

The current from this filter is pretty gentle so it can be used for Betta fish tanks as well.

his internal filter does not come with a flow controller.

Pros

  • Small and compact
  • Quiet

Cons

  • No adjustments
  • Not fully submersible

Price

CCheck latest price and customer reviews at Amazon here

So these are the best internal filters for aquarium.

Benefits of internal filter

Internal aquarium filters are also called as submersible aquarium filters. Some internal filters are fully submersible and some are partial submersible.

They are very inexpensive and very good for the filtration of small tanks, especially tanks below 20 gallons.

They are a very good supplement if your large tank has extra bio-load and needs more filtration. Usually, they’re put in the corners of the large tanks. Most internal filters come with suction cups, so you can easily stick it on the side glass or on the bottom. 

The good thing about these internal filters is they are very small and if you can place them in one of the back corners of your aquarium then it will not mess up the look. 

They are very quiet as well. They are so quiet that you can’t even hear it. Also, they are very easy to set up and maintain.

Overall the benefits of internal filters are as follows:

  1. Cheap
  2. Quiet
  3. Easy to set up
  4. Easy to maintain

How does an internal aquarium filter work?

An internal aquarium filter is submerged into the tank. It then sucks the water and pumps it through its filter media which usually consists of a sponge. You can also replace the sponge with any other filter media of your choice in most of the internal filters.

How to set up an aquarium internal filter?

It is very easy to set up. You can place it in one of the back corners or at the bottom. Preferably find a place where it will not be visible. 

Most of the internal filters come with media cartridge so just insert it into the filter and you are good to go. 

Also, most internal filters come with suction cups so you can stick it on the glass wall.

If your filter doesn’t come with media cartridge then you can easily find out what kind of cartridge it will require by looking on the back of the filter or the box.

Another easy way to find the ideal filter cartridge to go on Amazon and the type in your internal filter name and visit its sales page, scroll a little bit and under “Frequently bought together” title there will the suitable media cartridge for your internal filter.

Pretty cool, huh?

With that out of the way, let’s move towards the list of the best aquarium internal filters available in the market.

Best Aquarium Internal Filter image

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