Our top pick for the Best Aquarium Internal Filter is the Marineland Magnum Polishing Internal Canister Filter for its high 290 GPH flow rate for large aquariums up to 97 gallons, adjustable dual-chamber design allowing customized filtration, included micron cartridge enabling crystal clear polished water, and combination of mechanical, chemical and biological filtration.
The most critical component of an aquarium to ensure the health of your fish is the filtration system, which removes fish waste and prevents the accumulation of harmful toxins.
If you have limited space for a bulky external model, internal aquarium filters provide a compact solution that resides directly inside the tank. This guide outlines key considerations in choosing an in-tank filter, provides reviews of leading models based on firsthand testing, and offers best practices in routine cleaning and maintenance to optimize performance.
What may seem like an ancillary purchase, in fact, directly impacts the quality of life for your fish and the sustainability of your mini-ecosystem. By investing in an appropriate filter sized for your tank volume and stocking level, establishing conscientious cleaning habits, and monitoring ammonia and nitrate levels through weekly water testing, you can maintain clear, safe water for your aquatic pets to thrive.
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Our Recommendations for the Best Internal Aquarium Filters
Based on our testing and experience, the following are our top picks for internal aquarium filters. These are the best options that you can trust for a healthy and clean fish tank. They also span over a wide range of budgets, so everyone can find a filter that suits their budget.
Marineland Magnum Polishing Internal Canister Filter
Our top recommendation - Marineland's Magnum Polishing Internal Canister Filter is an excellent option for aquarium owners looking for high-capacity, versatile filtration. With a flow rate of 290 gallons per hour, this filter is suitable for aquariums up to 97 gallons.
A key advantage of this canister filter is its adjustable dual-chamber design. The chambers can house activated carbon or other customized filter media to suit your needs. The included micron cartridge also enables high-efficiency water polishing for crystal-clear water. You'll appreciate conveniences like the submerged motor for quick, priming-free startups.
When used for continuous three-stage filtration, the Marineland Magnum combines mechanical, chemical, and biological filtration. The Rite-Size floss sleeve traps debris, activated carbon removes odors and impurities, and the large surface area facilitates beneficial bacteria growth. Converting to a dedicated water polishing setup is straightforward - simply replace the media canister and floss sleeve with the micron cartridge.
- Powerful 290 GPH flow rate for up to 97-gallon aquariums
- Adjustable dual-chamber design for customized filtration
- Included micron cartridge for crystal clear polished water
- The submerged motor enables quick, priming-free startups
- Combination of mechanical, chemical and biological filtration
- Micron cartridge works best with added diatomaceous earth
- Does not include tubing or accessories besides filter media
For aquarium owners prioritizing versatility, the Marineland Magnum Polishing Internal Canister Filter is hard to beat. With customizable chambers and dedicated water polishing ability, this filter provides comprehensive filtration solutions. The 290 GPH flow can handle almost any aquarium setup. If you can tolerate some motor noise, this Marineland filter will likely exceed your expectations for crystal-clear water and healthy aquatic life.
Tetra Whisper EX Power Filter
The Tetra Whisper EX Power Filter is an excellent option for both beginning and experienced aquarium owners looking for silent, efficient filtration. Available in sizes accommodating aquariums from 10 to 70 gallons, it offers strong water flow up to 240 gallons per hour to prevent debris accumulation. Continuous water circulation also maximizes oxygenation for healthy tanks.
Easy installation right out of the box and mess-free cartridge swapping make maintenance straightforward. The multi-stage filtration system directs water through densities of floss to trap particles, while activated carbon eliminates discoloration and odors. A Bio-Scrubber corner filter provides biological filtration to decrease ammonia and nitrites. Customers also give high marks for noise level, sheerness, easy cleaning, and suction power.
Compact and quiet, the filter simplifies aquarium care while keeping tanks crystal clear. Reasonable pricing from $23 to $35 makes it budget-friendly too. You can rely on this workhorse filter to handle turtle habitats as well, granted water stays adequately topped off. It's a top choice for good reason – the Tetra Whisper EX Power Filter offers silent, effective filtration to suit diverse applications.
- Whisper-quiet operation
- Easy no-drip cartridge changes
- Suitable for a wide range of aquarium sizes
- Handles turtle tanks
- Affordable pricing
- Requires regular cartridge replacement
- Not designed for saltwater tanks
- Occasional motor noise
Reliable and appropriately priced, the Tetra Whisper EX Power Filter delivers simplified aquarium filtration and maintenance. Unobtrusive operation and multi-stage cleaning capacity position it among the best internal power filters for home freshwater aquariums up to 70 gallons.
Penn-Plax Cascade 600 Fully Submersible Filter
The Cascade 600 is another excellent fully submersible aquarium filter that provides powerful 3-stage filtration for crystal clear water. Quietly delivering 175 gallons per hour, it's ideal for freshwater and saltwater tanks up to 50 gallons.
Utilizing two filter media chambers, the Cascade 600 comes equipped with a refillable carbon cartridge to remove odors, discoloration and chemicals, as well as a bio-sponge that optimizes beneficial bacteria growth. Together, these media provide thorough chemical, biological and mechanical filtration to trap debris and keep water pristine.
An accommodating design with an adjustable flow switch and directional nozzles allows you to easily control the output. Furthermore, the filter can be positioned vertically or horizontally using the four suction cups. Venturi aeration eliminates the need for an air pump by oxygenating water directly. The aerating spray bar evenly distributes filtered water across the tank surface.
- Powerful 3-stage filtration for crystal-clear water
- Quiet operation at 175 GPH flow rate
- Ideal for freshwater and saltwater tanks up to 50 gallons
- Comes with a refillable carbon cartridge and bio-sponge
- Adjustable flow switch and directional nozzles for control
- More expensive than some competitors
- Spray bar output may be too strong for bettas or small tanks
In summary, the Cascade 600 Submersible Filter is a feature-rich 3-stage filtration system perfect for crystal clear water in freshwater and saltwater aquariums up to 50 gallons. If you don't mind paying more for quality filtration with customizable flow control, this is one of the best internal filters available.
Fluval U2 Underwater Filter
Our next pick - Fluval's U2 Underwater Filter provides efficient three-stage filtration for aquariums up to 30 gallons. As the second smallest model in Fluval's U Series, the U2 combines practical features with versatile installation options at an affordable price point.
With dimensions of 5 x 7 x 9.5 inches, the U2 has a compact and sleek black design that blends seamlessly into aquarium setups. Its flip-top lid enables quick access to the filter cartridge for hassle-free maintenance, while the easy-grip water control panel allows adjustment of the three-way flow output. Positioned horizontally, vertically or with an integrated spray bar, the U2 caters to different tank dimensions and customized current patterns.
The U2's suitability for freshwater, saltwater, and reptile tanks of up to 30 gallons makes it a good choice as either a standalone filter for smaller setups or a supplementary system for larger environments. Its three filtration stages efficiently improve water clarity and quality. The poly/carbon cartridge combined with BioMax biological media provides thorough mechanical, chemical, and biological filtration.
When it comes to user-rated performance metrics, customers highlight the U2’s quiet operation, thorough cleansing ability, adequate flow rate, and overall ease of maintenance. While opinions vary based on specific setups, the consensus aligns with Fluval’s reputation for well-designed, functional aquarium accessories.
- Three-stage filtration with BioMax biological media
- Adjustable three-way flow control
- Flip-top access lid for easy maintenance
- Sleek, space-saving design
- Versatile positioning options
- The flow rate may be too low for some setups
Aquarists seeking an efficient, conveniently sized filter for small freshwater or saltwater tanks should definitely consider the Fluval U2, a feature-packed option at a reasonable price point. With adjustable flow output and versatile positioning, it enables customized three-stage filtration to suit different needs. Ultimately, the U2’s balance of form, function and affordability makes it a compelling choice as the best aquarium internal filter for nano reefs and planted tanks up to 30 gallons.
COODIA Internal Green Water Killer Aquarium Filter
The COODIA Internal Green Water Killer Aquarium Filter Tank U-V Pump is one of the best internal aquarium filters for eliminating green water algae blooms. Installing this quiet yet powerful 5-watt, 75-gallon pump is remarkably easy - simply submerge it into the aquarium tank, plug it in, and let its sterilizing UV light get to work.
Within days, this small but mighty workhorse noticeably cleared the pea-green haze in my 55-gallon community tank. Its unique 4-in-1 system not only filtered algae spores but also oxygenated the water, generated a beneficial current and reduced future algal growth without chemicals. Though designed for larger tanks, it still fits smaller aquariums when positioned horizontally.
- Kills green water algae fast
- Creates healthy water flow
- Built-in UV clarifier
- Low energy consumption
- Easy set up
- Long 9-ft power cord
- Bulky size in nano tanks
- No indicator light
By preventing green water outbreaks without ongoing costs, this submersible green killing machine offers great value for money. Your tank inhabitants will be able to swim freely in their crystal habitat, and you'll have peace of mind knowing that your fish are healthy. For its sheer effectiveness against stubborn algal blooms, the COODIA UV Filter Pump earns a glowing recommendation.
Aqueon QuietFlow 50 LED PRO Aquarium Fish Tank
Next on our list, the Aqueon QuietFlow Power Filter is designed to be one of the best internal aquarium filters available. With higher flow rates of up to 250 gallons per hour and four advanced filtration stages, this filter promotes crystal-clear water and healthy, active fish.
An internal pump design is a standout feature of this unit, allowing for quiet operation, continuous flow, and automatic restarting if power is interrupted. The lack of an external pump also eliminates the risk of leaks and allows for a slimmer profile that blends into your aquarium décor.
When it comes to filtration, the Aqueon QuietFlow delivers an outstanding performance. Its dense floss cartridge traps debris and particles in stage one. Activated carbon in stage two removes discoloration, odors, and toxins. The patented Bio-Holster in stage three gives beneficial bacteria surface area to convert ammonia and nitrites. Lastly, the diffuser grid optimizes oxygenation, which reduces noise and keeps fish lively.
Replacement cartridges are readily available in three sizes to match your model’s flow rate. The integrated LED light indicates when it’s time to swap the cartridge, taking the guesswork out of maintenance.
- Internal pump for quiet and leak-free operation
- LED change indicator for easier maintenance
- Advanced 4-stage filtration for healthy water
- High flow rates up to 250 GPH
- Broad 3-year warranty
- Filter cartridges require replacement every 4 weeks
With superior biological and chemical filtration, the Aqueon QuietFlow Power Filter is an excellent choice for crystal-clear water and low maintenance. If you want next-level aquatic life without disruptive hum or clutter, this quality filter is worth the investment.
Fluval C2 Power Filter
The Fluval C2 Power Filter is an excellent choice for both freshwater and saltwater aquariums between 10 and 30 gallons. With its 5-stage filtration system, it provides superior mechanical, chemical, and biological filtration to keep water clean and clear.
Two foam media pads effectively trap debris, while a chemical filter with activated carbon removes odor, discoloration and impurities. The biological filtration includes a Bio-Screen pad and a Biological Trickle Chamber loaded with C-Nodes. Together, they provide abundant surface area for beneficial bacteria to thrive. An integrated re-filtration system also allows you to reduce the flow rate when needed without compromising performance.
Customers praise the C2 filter for being easy to clean, with foam media that slides out smoothly. It also earns positive ratings for suction power and low noise levels. The C2 provides premium multi-stage filtration and quiet operation.
- 5-stage filtration removes debris, toxins and ammonia
- Re-filtration system controls the flow rate
- Foam media is easy to remove and rinse
- Good suction power and low noise
- Sleek modern design
- Replacement media can be costly over time
- Setup instructions could be more detailed
If you need a high-performing internal canister filter for small freshwater or saltwater tanks up to 30 gallons, the Fluval C2 Power Filter is a superb choice. With its multi-stage filtration system and convenient design, it produces clean and healthy water while also being quiet and energy efficient. If you want superior water quality without the hassle, the C2 filter is easily one of the best options on the market.
AquaClear 50 Power Filter
Another excellent pick is AquaClear's Power Filter, one of the most versatile and efficient hang-on aquarium filters available. With five models to choose from, it can accommodate tanks from 5 to 110 gallons and provides superior mechanical, chemical, and biological filtration.
A key advantage is the filter's large media volume and extended water contact time, enabling optimal nutrient export and waste processing. You get up to seven times more capacity compared to rival units, supporting more beneficial bacteria to eliminate ammonia and nitrites. The unique re-filtration system also lets you reduce the flow rate without affecting performance.
As for setup and maintenance, the filter couldn't be simpler. Installation takes seconds, while the intuitive design facilitates access to the removable filter basket and media. Expect to clean it biweekly for maximum efficiency.
- Energy-efficient operation reduces running costs
- Adjustable water flow to suit aquarium needs
- Multi-stage filtration removes a wide range of contaminants
- Quick and straightforward installation process
- Easy access to maintain filter media every 2 weeks
- The high flow rate may disturb delicate species
For its blend of value, customization, and high-capacity biological and mechanical filtration, the AquaClear Power Filter is one of the best aquarium internal filters. It outperforms rival units for waste export and water quality in tanks up to 100 gallons.
AquaMiracle Aquarium Internal Filter
The AquaMiracle Aquarium Internal Filter is an excellent choice for fish tank filtration and oxygenation. With sizes available for aquariums from 5 to 100 gallons, you can find a model suitable for tanks small and large. The 3-stage filtration system uses a combination of coarse, carbonized, and fine sponges to thoroughly clean aquarium water. Dual water outlets promote even circulation, while the air venturi and tubing increase oxygen levels.
The fully submersible design includes an epoxy-sealed motor that undergoes rigorous safety testing. With flow rates up to 130 gallons per hour, this filter can handle busy aquariums with ease. The maximum lift height of 2.5 feet gives flexibility for positioning inside the tank.
Monitoring filter performance is straightforward thanks to the transparent housing. You can view the 3-stage sponges and determine when they require cleaning or replacement. Widely available replacement sponges also make maintenance simple.
In terms of value for money, the AquaMiracle filter ranks well. Prices range from an affordable $9.99 for smaller tanks up to $26.99 for heavy-duty 100-gallon models. With quiet operation and effective 3-stage filtration, you receive reliable performance for the investment.
- Suitable for tanks from 5 to 100 gallons
- Affordable pricing from $9.99 to $26.99
- Powerful 3-stage filtration system
- Transparent housing for easy monitoring
- Provides supplemental aeration
- Nothing we could think of
The AquaMiracle Internal Filter provides robust and hassle-free filtration. The combination of strong performance, safety assurances, and simplicity makes this a leading choice for clear and healthy aquarium water. Positioning two filters on larger tanks enhances circulation and filtration for optimal results.
NICREW Aquarium Submersible Filter
NICREW's Aquarium Submersible Filter is great for both freshwater and saltwater tank owners looking to upgrade their filtration system. With sizes ranging from a compact 2-5 gallon Mini for nano tanks up to a powerful 40-66 gallon Magi 1000 model capable of handling larger aquarium volumes, NICREW ensures high-quality biological and chemical filtration for tanks of varying capacities.
Activated carbon and fine filter foam work effectively to trap debris, absorb odors, and facilitate thorough waste breakdown while also generating a healthily oxygenated, well-circulated current within the tank. An adjustable air regulator allows you to customize water flow levels to suit more sensitive species like shrimp or delicate fish. Quick and straightforward assembly combined with included suction cups makes set up and maintenance simple.
With pricing from an affordable $8.99 for the Mini up to $23.99 for the top-of-the-line Magi 1000, NICREW submersible models offer robust filtering capabilities without breaking the bank. If superior waste management and water quality are what you seek, NICREW has a model sure to keep your tank environment in top shape.
- Multiple size options to fit tanks from 2 to 66 gallons
- Effectively filters biological and chemical waste
- Generates healthy water circulation and oxygenation
- Customizable flow levels safe for all species
- Easy assembly and maintenance
- Foam needs occasional replacing
With reliable biological, chemical, and mechanical filtration, NICREW's submersible models check every box. The customizable flows and sizes for tanks of different capacities ensure superior water quality is within easy reach. We recommend the NICREW Submersible Filter as a user-friendly option effective at keeping water clean and fish healthy in freshwater and marine setups alike.
Buying Guide - Things to Consider in an Internal Aquarium Filter
With the available options on the market, choosing the best internal filter for your fish tank can easily get stressful. We came up with a list of the crucial factors to consider before making up your mind to make the task much easier.
One of the most important factors is selecting the properly sized filter for your aquarium. An undersized filter will struggle to keep up with waste production, while an oversized unit takes up valuable swimming area and can create too much water turbulence. For a detailed overview of fish tank cost considerations when planning an aquarium system, check out our aquarium cost guide.
Additionally, the physical dimensions of a filter are key. Make sure any internal filter will properly fit in your aquarium without crowding fish. Try to choose a filter that is not too big but still provides enough power and performance to keep your fish tank clean and healthy.
Filtration Methods & Media
The type and quality of filtration media a filter uses directly impacts its performance. Most internal models utilize a combination of mechanical, biological and chemical filtration.
- Mechanical media physically traps debris and particles through porous pads or floss
- Biological media hosts beneficial bacteria that break down waste and toxins
- Chemical media absorbs odors, discoloration and medications through activated carbon
Higher-end options allow the customization of filtration media to suit your tank’s needs. Also, consider if an internal filter features multiple filtration stages or compartments for the most thorough cleaning capability.
Flow Rate Capacity & Tank Size Matching
A filter must be appropriately matched to the aquarium size to function properly. The filter’s flow rate capacity - measured in GPH - must align with the tank volume.
Additionally, consider factors that can impact a filter's flow rate like accumulation of debris on media pads that may clog the unit over time. Purchase an internal filter with a flow rate rating suitable for the high end of your aquarium's size to account for these variables.
As a general rule of thumb, the following guidelines can help you choose the right size filter:
- 10-30 gallon tanks: Seek filters with a 100+ GPH flow rate
- 30-50 gallon tanks: Choose filters with a 150-200+ GPH flow rate
- 50-75 gallon tanks: Look for units with a 200-300+ GPH rating
Many internal power filters rely on an electric motorized impeller to circulate water. Impellers can generate noticeable humming or buzzing noises. Check the product specifications for noise level ratings measured in decibels, or read reviews to identify quiet operation.
For particularly noise-sensitive environments like bedrooms, an ultra-quiet submersible filter may be preferential over standard internal options, which tend to be louder.
Ease of Installation
Look for an internal aquarium filter that can be easily installed without special tools or complexity. Most feature either suction cup, bracket, or rim attachment options to neatly fit inside your tank.
Ideally, the filter should also provide quick access latches that allow you to quickly open the unit to maintain, replace or clean filtration media when needed without requiring a full removal.
Selecting the right type of aquarium filter requires careful consideration of your tank size, stocking levels, and overall goals. To help determine the perfect tank to establish a healthy, decorative marine environment, check out our fish tank guide. As we have covered, filters come in varying shapes and capacities to accommodate different setups - from compact internal models for small tanks to high-flow canister filters for heavily stocked environments.
While an ideal filter setup requires some research on your part, the good news is that today's filters are highly effective and energy efficient. Brands like Fluval, Marineland, and Aquaclear offer quality options to suit tanks large and small. Investing in the right filtration system tailored to your tank is well worth the effort. For those who are looking for the filtration systems specifically recommended for large aquariums, check out our guide.
What has your experience been with different filter types and models? Please share your thoughts in the comments section below! I would be happy to continue the conversation with fellow aquarists.
Thank you for reading!