Yellow Fish Inside Aquarium

Top 5 Best Internal Filters For Your Aquarium (2020 Review)

In order to keep your fish as healthy as possible, you’ll want to provide them with the best aquarium products. Keeping your fish’s tank clean is a priority, so that is why you need to put a lot of consideration into the filter that you purchase for them. But how do you decide what the best internal aquarium filters are?

An internal aquarium filter is a fully submersible filter that’s great for beginners. It’s the perfect addition for increasing water flow in your aquarium.They are generally best for aquariums that are 20 gallons or less.

After considering all the options our top picks were…

Results Summary

When it comes to any pet products, there are always a lot of options to choose from. So, how do you decide which internal filter is the best choice for your aquarium? That answer might be different for every fishkeeper, but here are some of the best options based on the popularity, price and quality.

Best-All Rounder

Fluval Underwater Filter

The Fluval Underwater Filter uses a unique filtration system that utilizes 3 different stages. First, foam filter pads remove large particles, allowing the poly carbon pads to more easily remove small debris afterwards.

Fluval Underwater Filter

The best allrounder is the Fluval Underwater Filter. This particular filter comes in a wide variety of sizes and it’s easy to use and maintain. It makes very little sound and there are multiple ways that you can position the filter and adjust the water flow. 

Best on a Budget

Tetra Whisper In-Tank Filter

It’s a fairly basic filter that uses a dual-sided mesh to clean the tank. The one side has a Bio-Bag filter cartridge to catch debris and then the other side is a Bio-Scrubber for biological filtration.

Tetra Whisper In-Tank Filter

If you’re looking for a filter that works well for being an affordable price, then the Tetra Whisper In-Tank Filter is for you. It’s one of the most basic internal aquarium filters, but it works well for the great low price.

Editor’s Choice

Aqueon Quietflow Internal Power Filter

This internal filter is recommended due to its small size and quiet sounds. It’s fully submersive and it has 3 different methods of cleaning the water.

Aqueon Quietflow Internal Power Filter

While it might not be as versatile as some of the other options, the Aqueon Quietflow Internal Power Filter is a great option for beginners looking for a quality filter. It’s easy to use and it uses a unique 3-step filtration process to keep the tank as clean as possible.

Value Editorial

Before you decide exactly which filter is best for your aquarium, there are some things you should consider. Different filters might work better for different enclosures, so be mindful of that when selecting an internal filter for your aquarium.

How Do Internal Aquarium Filters Work?

An internal aquarium filter is designed to rest in the back corner of the aquarium and the outlet should be just below the water’s surface. 

The internal filter works by sucking water in through the bottom of the filter…

The internal filter works by sucking water in through the bottom of the filter. The water is then brought through a rough sponge that is able to trap the debris as the water passes. This special sponge contains bacteria that lives in the oxygen-rich water that passes through. This bacteria converts the bad parts of the water to beneficial items to make the water clean once again.

Once the water has gone through the filter, it releases the clean water back into the tank. Each filter is slightly different, but most internal aquarium filters do this by either spraying it back out or releasing it in a waterfall-like flow. The spray feature is often an optional feature that allows the clean water to be more evenly dispersed in the tank. 

How to Set Up an Internal Aquarium Filter

Internal aquarium filters are actually fairly easy to set up. First, you’ll need to decide on a spot to place your filter. As mentioned earlier, the back corner of your aquarium is generally the best place to put it. Internal filters usually have suction cups on the back to allow you to easily attach it to the desired spot. 

The filter will come with an air tube that needs to be attached to the spot above where the water comes out. This tube will bring some air into the tank while the clean water is being poured back into the aquarium water.

The air is then mixed in with the water to keep your aquarium oxygenated. The tube does create bubbles in the tank, so some fishkeepers decide not to use it. For example, if you have live plants in your tank, it’s better not to use the tube for air because the air will take away the carbon dioxide that the plants need. Check out the video below to see how to use an internal filter.

How To Use Aquarium Filter

Placing the Filter

When placing the filter inside the aquarium, make sure it’s completely submerged in the water. If part of the filter is sticking out of the water, it could heat up and burn the coil. So, make sure to keep the filter completely inside the cool water. However, if you are using the air tube, make sure the end of that tube sticks out of the tank. If the end of that tube falls in the water too, then it defeats the purpose of it.

When placing the filter inside the aquarium, make sure it’s completely submerged in the water…

Once your internal filter is in the aquarium, you can simply plug it in to the nearest outlet and the filter will start operating. If you feel that your filter is too loud or producing too many bubbles, you can move it deeper into the tank to make it quieter. However, remember that you need to clean it regularly, so it’s best to place it in a spot that is easy to reach without disturbing your fish.

Benefits of Internal Aquarium Filters

This type of filter is great for beginners because it’s easy to set up and it can be found at nearly all pet stores. They are more reasonably priced than some of the other filters and the cost to maintain these filters is also very low. 

These filters are also easy to operate. They use less electricity than other filters and most brands are generally very quiet for an aquarium filter. So, if you are looking for a basic filter for your first aquarium, this is a great option to choose.

When Should You Use a Different Filter?

Internal aquarium filters are typically only ideal for tanks 20 gallons or less. They will usually not suffice being the only filter in a larger aquarium. However, even in a small aquarium, the filter could still take up too much space depending on which size filter you choose.

Also, since this filter needs to be kept inside the water of the tank, this can cause problems when you need to clean it. Even though you need to clean the sponge inside often, you’ll have to reach your hand inside the water to grab the filter and take the sponge out. 

TIP

The bacteria on your hands could get in the water and harm the fish simply by taking out the filter often to clean it. So, be extra careful when cleaning this filter. If this concerns you, then you might want to consider a different type of filter.

Fish Swimming inside an Aquarium
Fish Swimming inside an Aquarium

What There Is To Know About Cleaning…

Even though the filter is in place to keep the tank clean, you still need to clean the filter yourself. Specifically, you need to clean the sponge inside the filter or replace the substrate inside the filter regularly. 

Every few weeks, you should rinse the sponge off in old tank water to help remove any trapped debris. It’s important that you avoid using tap water because the chlorine in the tap water could kill some of the good bacteria on the sponge. If that happens, the filter won’t work well until that bacteria has time to reform. That’s why it’s best to just use the water that’s in the tank.

If you don’t clean your aquarium on a regular basis, the debris will continue to build up, making it harder for the filter to function properly…

If you don’t clean your aquarium on a regular basis, the debris will continue to build up, making it harder for the filter to function properly. This will cause the flow rate to drop significantly and the filter won’t be able to remove as much waste from the tank as usual. A filter that runs too slow could affect the oxygen levels of the aquarium as well.

TIP

It’s best to check on your filter often to make sure it’s still properly cleaning the tank. If you find yourself needing to clean it a lot more than when you first purchased it, you might want to consider upgrading to a new filter to keep your aquarium as healthy as possible. 

Internal Aquarium Filter Reviews

Once you’ve decided that an internal aquarium filter is what you need for your tank, you’ll need to decide which one is right for you. Each filter has their own unique features, so choose one that you think will be a good fit for your specific aquarium. 

Some aquarium tanks might come with a fitted internal filter, but if yours doesn’t, then you’ll need to decide on the perfect one yourself.

Editor’s Choice

Aqueon Quietflow Internal Power Filter

This internal filter is recommended due to its small size and quiet sounds. It’s fully submersive and it has 3 different methods of cleaning the water.

Aqueon Quietflow Internal Power Filter

This internal filter is recommended due to its small size and quiet sounds. It’s fully submersive and it has 3 different methods of cleaning the water. It can make the water clear using dense foam to remove debris, activated carbon to get rid of toxins and odors, and the BioGrid to remove ammonia and nitrates like a sponge would. 

If needed, you can change the water flow by removing the tube that the water flows out of and adjusting it manually. This can help you to ensure that you get the perfect amount of flow in your aquarium. The 10-gallon filter has a height of about 5.75 inches and a length of 3 inches. 

Specs

Pros

  • It’s a smaller, more compact model.
  • You can direct the water flow, allowing you to place it either horizontally or vertically.
  • It’s easy to take apart and maintain.
  • It comes in different sizes that are made for 10-gallon tanks all the way up to 40-gallon tanks.

Cons

  • It isn’t as durable as some of the other filter options.
  • It only uses Aqueon Replacement Internal Filter Cartridges.
  • It’s a bit more expensive than other options.

Penn Plax Cascade 300

The Cascade 300 is another fully submersible filter that uses an activated carbon cartridge to remove any harmful chemicals, toxins, and other contaminants. It has a large filter cup that allows you to select your own filter medium if you’d like.

Penn Plax Cascade 300

The Cascade 300 is another fully submersible filter that uses an activated carbon cartridge to remove any harmful chemicals, toxins, and other contaminants. It has a large filter cup that allows you to select your own filter medium if you’d like. You can also easily replace and clean the filter as needed.

It has a large filter cup that allows you to select your own filter medium…

It also has a pump that can be adjusted and it has a spray bar feature that you can use to more evenly distribute water throughout the tank. So, you can choose the way the water flows to help better suit the needs of your aquarium. It delivers 70 GPH, which is fairly average for a 10-gallon internal filter.

Specs

  • Maximum Gallons – 10
  • Gallons per hour – 70
  • Medium – Comes with internal sponge, but you can change to your own substance.
  • Positioning – Vertical or Horizontal
  • Water Return – Pump head is adjustable and spray bar is included.

Pros

  • The refillable cartridge allows you to use the substance of your choice.
  • The adjustable water pump and spray bar allow for more choices on how to control the water flow.
  • It has a clear chamber, allowing you to easily view the contents inside.
  • It circulates water faster than other similar filters.
  • The price is reasonable.

Cons

  • It’s only for tanks that are 10 gallons or less. However, there are other similar models that are larger.
  • The way it’s designed could accidentally allow some water to bypass the sponge.

Best-All Rounder

Fluval Underwater Filter

The Fluval Underwater Filter uses a unique filtration system that utilizes 3 different stages. First, foam filter pads remove large particles, allowing the poly carbon pads to more easily remove small debris afterwards.

Fluval Underwater Filter

The Fluval Underwater Filter uses a unique filtration system that utilizes 3 different stages. First, foam filter pads remove large particles, allowing the poly carbon pads to more easily remove small debris afterwards. Then, the Biomax filter nodes biologically balance the water to give your aquarium the healthiest environment possible.

This filter has a top that easily flips open to allow you to quickly replace and clean the filter without disturbing your aquarium at all…

This filter has a top that easily flips open to allow you to quickly replace and clean the filter without disturbing your aquarium at all. To help give your aquarium the proper water flow, you can adjust it between a top, middle, and bottom output. All you have to do is turn a knob at the top to easily switch to these different modes.

It’s one of the quieter filter options and it comes in multiple sizes to fit different sized aquariums. 

Specs

  • Maximum Gallons – 12 to 65
  • Gallons per hour – 65 to 260
  • Medium – Fluval foam filter pad, poly/carbon pad, and Biomax.
  • Positioning – Vertical or Horizontal
  • Water Return – 3 adjustable flow options
  • See the full specs for the Fluval Underwater Filter

Pros

  • You can easily flip the top off to replace the filter.
  • It has 3 different water flow options.
  • It comes in different sizes, all the way from 12 gallons to 65 gallons.
  • It barely makes any sound.
  • It’s a good value.

Cons

  • It’s not the most durable option and it doesn’t seem to last as long as some of the others.

Best on a Budget

Tetra Whisper In-Tank Filter

It’s a fairly basic filter that uses a dual-sided mesh to clean the tank. The one side has a Bio-Bag filter cartridge to catch debris and then the other side is a Bio-Scrubber for biological filtration.

Tetra Whisper In-Tank Filter

This filter is another small, quiet filter. It’s available for 10-gallon, 20-gallon, and 40-gallon tanks. It’s a fairly basic filter that uses a dual-sided mesh to clean the tank. The one side has a Bio-Bag filter cartridge to catch debris and then the other side is a Bio-Scrubber for biological filtration. 

It comes with clips or suction cups to hold the filter upright in a submerged, vertical position. However, both of these methods are not the most durable way to hold the object, so it’s likely that the suction cups will stop clinging eventually. Since the filter itself is likely the most affordable option, you shouldn’t expect it to last forever either, but it works great short-term.

Specs

  • Maximum Gallons – 10 to 40
  • Gallons per hour – 80 to 170
  • Medium – medium Bio-Bag filter cartridges
  • Positioning – Vertical
  • Water Return – Waterfall flow only

Pros

  • It’s the cheapest option.
  • It’s very quiet.
  • It’s easy to install and maintain.
  • It comes in three different sizes, all suitable for a smaller aquarium.

Cons

  • It’s not very durable.
  • The position of the filter and the water flow is not flexible.
  • It’s larger than other similar products, so it takes up a lot of space in the aquarium.

Aquatop IF-201 Internal Filter

This internal filter is compact and quiet much like a lot of the other filter options. It’s designed for tanks that are 10 gallons or less and it can be placed either vertically or horizontally in the tank.

Aquatop IF-201 Internal Filter

This internal filter is compact and quiet much like a lot of the other filter options. It’s designed for tanks that are 10 gallons or less and it can be placed either vertically or horizontally in the tank. It uses an extra dense sponge for maximum filtration. The sponge can be washed and reused as needed. Plus, the filter can easily be taken apart and put back together, so changing and cleaning the sponge is not an issue. 

This product also has an optional spray bar attachment to allow the clean water to reach a wider range. You can also choose to include a Venturi-Line for additional oxygenation in your aquarium. These additional features are bonuses that can help you to make your filter more personalized to your aquarium’s needs.

Specs

Pros

  • It has a compact design that doesn’t take up too much space.
  • The flow rate can easily be adjusted.
  • It’s a good value.
  • The position of the filter and water flow is adjustable.

Cons

  • It’s flow rate is much lower than similar products.
  • It doesn’t last for a really long time.
  • It makes more noise than similar products.

Wrapping Up

After considering all the options our top picks were…

While all these filters are great options to check out, they each have clear positives and negatives to them. Each filter is better for different fishkeepers depending on what that person is looking for.

The best filter overall is the Fluval Underwater Filter due to its wide selection of unique features and variety of sizes. However, if you are looking for something on a budget, then the Tetra Whisper In-Tank Filter is the best option to get a functioning filter for the best price. Then, the editor’s choice is Aqueon Quietflow Internal Power Filter because it’s the best option for beginners looking for something that’s reliable and easy to use.

Internal filters are generally very basic and simple to maintain, but some will work better for your specific aquarium than others. Consider how much you’re willing to spend and what type of quality you’re looking for before selecting your internal filter.

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