An Internal aquarium filter is a fully submersible filter that is placed inside your aquarium to filter and remove any unwanted dirt particles inside the aquarium or fish tank.
Internal filters for aquariums are ideal for small fish tanks and are easy to set up and install compared to external aquarium filters.
They are also quiet during operation and have high filtration capability to ensure that your aquarium and fish tanks are clean and free of impurities and dirt.
How an Internal Aquarium Filter Works
Internal fish tank filters come in different sizes and in different designs to suit the needs of different users. They have different features depending on the brand.
However; all interior aquarium filters work the same. They are placed inside the fish tank or aquarium and are fully submerged in the water. Most filters include an outlet under the surface of the water.
The internal filter sucks water and pumps it through the filter media found inside the filter unit. The filter media removed different types of dirt from the water. When the media removed the dirt particles, the water is released back into the tank or aquarium.
A Brief Overview:
Pros
- Most internal filters are cheap and affordable.
- The aquarium filters are pretty easy to set up and install.
- They are also quite easy to maintain.
- Interior aquarium filters are quiet during operation.
- They are ideal for smaller fish tanks and aquariums.
Cons
- Internal filters have a smaller filter volume.
- The filter takes up some space inside the aquarium.
- The internal filters are not strong enough for large fish tanks.
Top 5 Best Internal Aquarium Filters
There are so many internal filters for aquariums in the market today, making it hard for beginners to identify a filter that suits their type of aquarium. Proper research is needed to identify the best filter that suits your needs and budget.
The good news is that we have carried out the research for you and have selected some of the filters that offer you value for your money.
Here are reviews for 5 of the best internal aquarium filters.
1) Fluval U4 Internal Filter
The Fluval U4 Internal Filter is a compact and versatile internal filter that is ideal for aquariums up to 240 L. It comes with many useful features that ensure efficiency and reliability. The aquarium filter includes removable filter media inserts and a system that is easy to clean and maintain.
The internal filter for aquarium utilizes 3-stage filtration. It has an adjustable 3-way flow control: the top output for circulation and oxygenation, an integrated spray bar for a smooth and even flow, and the bottom output for deepwater tension increased water movement and vital aeration.
The filter is easy to set up and use. The outflow of the aquarium filter can be regulated and it can be attached vertically or horizontally in the aquarium.
Fluval U4 Internal Filter can be used as a primary filter in small aquariums or as a complementary filter for larger aquariums or fish tanks. It can be placed at the bottom of low water level tanks.
The filter features a filter cartridge that can be used for inserting the Fluval Clean & Clear media. It includes a convenient flip-top lid that provides you with quick and easy access to the filter cartridge for easy maintenance or replacement.
Pros
- The filter includes Fluval BioMax biological media.
- It can be used for freshwater, saltwater and reptile environments.
- The outflow can be placed vertically or horizontally.
- It is designed for aquariums of a capacity of up to 240 L.
- The filter comes with a filter cartridge that can be used for inserting the Fluval Clean & Clear media.
- It includes a flip-top lid that allows you to quickly and easily access the filter cartridge for easy maintenance or replacement.
2) Marina i25 Internal Filter
Marina i25 Internal Filter is a compact yet powerful internal filter for aquarium that is ideal for aquariums of up to 6.6 gallons.
It is designed to keep the water in your aquarium clean and healthy to ensure that your fish has a great environment to thrive in. The filter is ideal for an aquarium with goldfish. It not only removes dirt but also removes pollutants and odor.
The filter is easy to set up and assemble since it is attached to the interior of the tank using strong suction cups. It traps dirt and debris inside the cartridge to ensure that the water is clean and healthy. The cartridge provides effective 3-stage filtration – mechanical, chemical and biological.
When the water is filtered, it returns to the aquarium through a waterfall spout, which generates continuous oxygenation to ensure that the water is fresh. The Marina i25 Internal Filter is backed by a 2-year warranty.
See also: Fish tank canister filters
Pros
- The filter has a zeolite chamber where ammonia is removed from the water.
- It features a cartridge with carbon to eliminate odor and pollutants.
- The aquarium filter is compact, making it easy to fit in any goldfish or tropical tank.
- It is suitable for aquariums of up to 6.6 gallons.
- The Marina i25 Internal Filter provides mechanical, chemical and biological filtration, making it ideal for an aquarium with goldfish.
- It attaches to the interior of the tank using strong suction cups, making it easy to set up and assemble.
- The interior filter comes with a 2-year warranty.
3) Tetra Whisper 20i
Tetra Whisper 20i is a reliable internal filter for aquarium that is well-designed for small aquariums that hold up to 20 gallons.
It operates quietly and effectively to remove impurities and pollutants from the water to ensure that the water is fresh, clean and healthy for your fish. The filter utilizes a medium Whisper bio-bag cartridge and a patented Bio-scrubber pad to provide 3-stage filtration.
The Whisper bio-bag cartridge contains a floss pad filled with activated carbon to remove dirt particles, odors, and discoloration in the water. It includes a Bio-scrubber pad to provide helpful bacteria to colonize and performs biological filtration and remove nitrogenous toxins found in fish waste.
The internal filter uses suction cups, making it easy to set up and install.
Pros
- The filter can be placed at high or low water levels and can, therefore, be used as a waterfall for low-water tanks or turtle tanks..
- It is easy to clean and maintain the internal filter for fish tanks.
- The filter provides 3-stage filtration to ensure that your aquarium water is fresh, clean and healthy for your fish to thrive.
- It has suction cups that make it easy to install and setup.
- The filter can be placed at high or low water levels and can, therefore, be used as a waterfall for low-water tanks or turtle tanks.
See also: best filter for small turtle tank
Cons
The bio-bag cartridge requires to be changed every month.
4) Aqueon Quietflow Internal Filter
The Aqueon Quietflow Internal Filter is a quiet filter that is capable of working even in tanks that have 2 inches of water. It is fully submersible in both a vertical and horizontal position.
The filter is designed to provide an excellent adjustable return flow rate. It is recommended for tanks that go up to 40 gallons.
The internal filter has a flow rate of 155 gallons per hour and uses two large cartridges to remove pollutants and impurities in water. It uses three-stage filtration with the first stage involving a dense foam to remove the dirt particles and the debris.
The water then passes through activated carbon to remove toxins. The third stage involves the patented BioGrid to remove bad odors or discolorations in the water.
Pros
- It uses the Aqueon replacement internal filter cartridges to ensure that the filtration process is fast and efficient.
- The water’s direction and height are fully adjustable.
- It is ideal for tanks that go up to 40 gallons and has a flow rate of 155 gallons per hour.
- The filter utilizes three-stage filtration to ensure that the water is clean, safe and healthy for your fish.
- It is reliable even in tanks that have 2 inches of water.
- The aquarium internal filter is fully submersible in both vertical and horizontal positions.
- It provides an exceptional adjustable return flow rate.
See also: Best external filters for aquariums
5) Penn Plax Cascade 600 Internal Fish Tank Filter
Penn Plax Cascade 600 Internal Filter is a durable internal filter from a reputable brand.
It is designed to provide you with physical, chemical, and biological filtration while improving aeration in your fish tank. It offers up to 175 gallons per hour of flow rate and is recommended for 20-50 gallon fish tanks or terrariums.
The filter features an activated carbon cartridge to remove harmful chemicals and toxins, odors, discoloration, and other contaminants in the aquarium water. It has an internal sponge that improves the colonization of beneficial aerobic bacteria for a healthy balance in the aquarium environment.
The pump head allows you to adjust the water flow and direction. The filter has a spray bar that can be used to divide the output water into many small streams to enhance your aquarium aeration and biological filtration.
Pros
- It includes a spray bar to let you enhance your aquarium aeration and biological filtration.
- The filter can be placed vertically or horizontally.
- The aquarium filter offers you up to 175 gallons per hour of flow rate.
- It comes with an activated carbon cartridge to remove harmful chemicals and toxins, odors and discoloration to ensure the water is clean, fresh and healthy.
- The filter includes an internal sponge to boost the colonization of beneficial aerobic bacteria for a healthy balance in the aquarium environment.
See also: Fluval or Marineland filter system for aquarium
The best internal filter for aquarium should effectively remove the different forms of dirt and impurities in your aquarium or fish tank. The ease of installation and maintenance is also an important factor to consider when shopping for the best aquarium internal filters.
The aquarium filters we have reviewed are some of the most reliable internal filters on the market.
The filters vary in price and in the features they offer. We hope that you have found a filter that suits your aquarium filtration needs and one that matches your budget.
Feel free to let us know which of the 5 internal filters you found to be more effective and reliable for your aquarium.
Reference
Aqua Fish: Differences between internal and external aquarium filters and diagrams, FAQ and Forum
JALJEEV: Are Internal Aquarium Filters Good? (Better Than External Filters?)