A filter is an indispensable device for your aquarium. There are two main types of aquarium filters currently, external and internal aquarium filters.
If the external aquarium filter needs a space outside the aquarium, an internal aquarium filter will fit neatly into the aquarium without any extra space.
That’s why many people prefer an underwater aquarium filter over an external one.
However, not everyone can easily choose the best underwater aquarium filter. There are countless products on the market and if you are not an experienced person, choosing the best device is a challenge for you.
So in this post we have prepared a list of the best underwater aquarium filters. You can refer to this list, along with some other useful information.
How Does Underwater Aquarium Filter Work?
An underwwater aquarium filter or internal aquarium filter is a device used to filter water in the aquarium, helping to remove waste and impurities from the water.
And this device is completely submerged in water and it won’t work without being placed at a suitable depth.
The device has a water intake hose in the aquarium, which then passes through the device’s filter media to remove waste and impurities.
After filtration, impurities and waste will be retained in the filtration media. The filtered water will return to the aquarium. It will work this way constantly to purify all the water in the aquarium.
If an aquarium does not have this device, the bacteria will grow and cause strong effects. Aquarium creatures will not live in a clean environment and are at high risk of illness, the worst case that can lead to death.
Top 5 Best Underwater Aquarium Filter 2021
#1 Tetra Whisper In-Tank Filter with BioScrubber (Best Quality)
Perhaps you no longer feel strange with a Tetra Whisper filter because it is a fairly commonly used device. This name is one of the indispensable products in any aquarium supplies.
And we can tell you that you can trust the quality of this filter. This product has many advantages that you should not miss.
This in-tank filter is an ideal budget option for those on a tight budget. It works relatively well and can effectively enhance the health of the organisms in the aquarium.
You can buy it at any aquarium store. Or you can order on Amazon if you do not want to go out. This product is at a reasonable price (if not cheap).
With this device, you can easily hang it on the edge of the tank thanks to a plastic clip. Therefore, you can save space and do not need any complicated settings.
This filter has a very good biological filtration capacity. Especially, BioScrubber pads play an important role in this biological filtration process. It will help keep up the most beneficial bacteria for your aquarium.
The filtered water will be returned to the aquarium as a waterfall. The movement of the waterfall will increase the oxidation capacity of the water, from which the water in the aquarium will be cleaner and healthier.
This product is highly appreciated for its easy cleaning and maintenance. However it is not appreciated by the flow rate. It may be too strong for some silent fish.
And it can be a bit noisy. The greater the flow rate, the louder the noise.
#2 Fluval Underwater Filter (Best Durability)
Fluval is also a formidable opponent on this list. Fluval is a well-known manufacturer of aquarium filters. This is also a reputable brand that you can trust.
This Underwater filter from Fluval is an ideal choice for aquariums up to 65 gallons. Usually, an internal aquarium filter is suitable for small-sized tanks. And if you’re looking for a medium-large aquarium filter, don’t overlook it.
This device is made of hard plastic, very strong and durable. This material is not as fragile as other cheap plastics. Therefore, it is not easily destroyed and it is also strong enough to survive long in the aquarium.
You do not need to worry about the filtering capabilities of this filter. You also do not need to worry about product maintenance or installation. It has a user-friendly design and you can easily replace filters or clean them by opening the lid.
In particular, this device can be vertical or located in the aquarium with flexibility. Therefore, you can choose an appropriate location in the aquarium for your filter.
You can also adjust the flow rate to match the organisms in the aquarium. A lower flow rate will suit quiet water fishes rather than a high flow rate.
However, many customers complained that this filter could leak dirt when you try to remove it from the aquarium. And this device is not a budget option.
#3 Aqueon Quietflow E Internal Power Filter (Best Features)
If you are looking for a small to medium sized aquarium filter, do not miss this filter. It is also an ideal choice for those who are looking for a filter for betta aquariums.
Aqueon is not a strange manufacturer either. You can easily find a product of this manufacturer at any aquarium supply.
This filter from Aqueon is a quality device, with mechanical, biofilter and chemical filtration. Especially, it has the ability to filter all the water in the aquarium in just a short time.
All filters of this filter function very well. They can effectively remove debris, waste, odors and impurities from the aquarium. They ensure the organisms in the aquarium live in a clean and healthy environment.
This filter also has a compact design to fit small and medium aquariums. It is not too large, does not occupy too much area in the aquarium.
You can easily attach the device to the wall of the tank with 4 suction cups. They stick very well and do not fall off even after prolonged contact with water. And when the device is fixed by the suction cup, it will not make noise due to impact on the tank wall during operation.
However, this device does not last as long as the other products on this list. Many customers think that it works very well but cannot last long.
#4 Hagen Elite Underwater Mini Filter (Best For Small Tank)
If you are looking for an ideal filter for your small size aquarium, this is your choice. This filter has a compact size and is extremely ideal for nano tanks or betta aquariums.
This filter has an extremely efficient mechanical and biological filter. It has the ability to quickly filter a 10 gallons tank and ensure all debris and waste in the aquarium is quickly removed.
This filter can also allow you to adjust the flow rate flexibly. For small sized tanks, the gentle movement of the water is also stronger than for large tanks.
Therefore, you need to adjust the low flow rate so as not to fear or affect the calm water creatures.
In particular, this filter also comes with an optional air tube. This optional air tube acts to create more air in the aquarium. It can also create venturi effects.
The point that customers appreciate about this filter is its design and compact size. It is not as bulky as other underwater filters, so you can cover them easily with decorative accessories.
This product comes with a reasonable price and you can easily find it at local stores or on e-commerce sites.
However, it has a minus point that the flow rate is still quite strong even if you have reduced it. It could also be due to the effect of a small tank.
#5 Marina I25 Internal Filter (Best Performance)
This is also another ideal filter for small sized aquariums. It has a compact size and great performance for those as large as 6.6 gallons. And Marina is also a manufacturer you can trust.
This filter consists of three filters, these filters work very well and have the ability to clean the aquarium quickly. These facilities include zeolite chamber, activated carbon filter and fine mesh filter.
In order, the water in the tank will go through these three stages of filtration to remove all impurities and impurities. Ammonia, odors, chemicals or debris will be completely removed after going through these filtration media.
This product is a durable plastic block, easy to install and maintain. It does not require much of your time and effort to install it inside the tank. You also won’t have to spend a lot of time on it for regular maintenance.
With a plastic lid on top, you can easily replace the filter media without removing the filter from the tank. No clutter occurred.
This filter makes no noise when operating. This is a big plus of the product for those who put aquariums in their bedrooms. However this filter cannot allow you to adjust the flow rate.
What To Consider When Choosing The Best Underwater Filter?
Before investing any underwater filter in your aquarium, take some time to consider. Haste will lead to disappointing results, and you may make mistakes.
Especially for beginners, the lack of experience is the reason for you to spend some time to research before buying a filter.
We have collected a few things that you should consider before buying an underwater aquarium filter.
#1 Does it easy to maintain?
The most important thing about a filter is to maintain its cleanliness to ensure the water in the aquarium is always in the best state. Therefore, this is the first factor that you should consider before buying.
A filter that allows you to easily clean and maintain should be a preferred option. Because the filter media come in direct contact with dirt and chemicals, you must remove them to avoid affecting the filtration quality.
#2 How many filter media?
Usually, an underwater aquarium filter is smaller than an external filter. Because of this feature, the filter media may be more limited.
So you should know how many filters you are going to choose. There are three main types of filtration media: chemical filtration, biological filtration and mechanical filtration. Many filters have only one or two filtering media.
If the filter has all three filter media, the efficiency and quality of filtration will be much better. But if you have no other choice but to choose a small size filter, it is very likely that it does not have all three types of filter media.
Meanwhile, a biofilter and mechanical filter are the best option.
#3 How about the flow rate?
Flow rate is also a factor that you should not ignore. The flow rate will directly affect the life of the creatures in the aquarium, especially the silent fish.
A larger tank will not have as many flow requirements as a small tank. For a small tank, all movements of water will become larger than for a large tank. So you should understand this factor well.
A large flow rate will produce greater oscillation than a lower velocity. It can scare small fish. High speed will also make more noise.
#4 Can you change the flow rate?
A filter that can allow you to change the flow rate should also be an option of your preference. Thus, you can change a flow rate that suits your aquarium instead of a fixed rate from the manufacturer.
#5 What is the warranty?
For any device, you need to pay attention to its warranty. If the two products are of similar quality and price, you should choose the one with a better warranty.
Many manufacturers warrant their products for several years. Some are more generous when raising that number and come with some better customer care regimes. In general, you should learn about the warranty because it won’t hurt you.
Final Verdict
Choosing an underwater aquarium filter is not a simple challenge, especially for beginners. However, if you take a moment to research the product you invest, this job will become simpler.
Don’t forget to consider the basic elements of a filter you need for your aquarium. Whether or not this device works well, whether or not it is worth your investment, is your choice.