Best Hang On Back (HOB) Aquarium Filters

Aquarium enthusiasts understand the importance of a clean and healthy aquatic environment for their fish and plants. Clear water not only displays the aquarium’s inhabitants more vividly but also ensures their overall well-being. This is where aquarium filtration systems come into play, and among the many types available, Hang On Back (HOB) filters hold a special place due to their ease of use and installation. HOB filters conveniently hang on the back of the tank, outside of the viewable aquarium space, and are ideal for aquarists looking for effective filtration without the need for complex setups.

HOB filters are particularly popular with both beginner and experienced fish keepers for several reasons. They are usually less expensive than canister or sump filters, require minimal setup, and are easy to maintain. Furthermore, many models offer a combination of mechanical, chemical, and biological filtration, providing a comprehensive cleaning solution for the aquarium. With their adjustable flow rates and the ability to customize media, HOB filters can be tailored to suit a variety of tank sizes and bioload demands.

When choosing the right HOB filter, it’s crucial to consider the filter’s flow rate, as it should ideally turn over the aquarium’s water volume at least four times an hour. Additionally, one should inspect the available space behind the aquarium, as some models might be bulkier than others. The ease of media replacement and the noise level of the unit are also important factors to consider. To aid consumers in their selection, we have meticulously researched and tested various HOB filters, evaluating their performance, durability, and user-friendliness to identify the most reliable options in the market. Our findings are intended to guide aquarists to make an informed decision that ensures the health of their aquarium’s ecosystem.

Top Hang On Back Aquarium Filters

Aquarium enthusiasts understand the importance of clear, healthy water. We’ve researched and identified the leading Hang On Back filters that provide superior mechanical, chemical, and biological filtration for various aquarium sizes. Our selection ensures optimal water quality and clarity, helping maintain a thriving aquatic environment.

Mighty Aquarium HOB Filter

Mighty Aquarium Hang On Back Filter - Aquarium HOB Filter - Adjustable Fish Tank Filter - Aquarium Filters - Nano Aquarium Filter - Fish Aquarium Filter - Hang On Back Aquarium Filter (1-3 Gallons)
  • [Beginner-Friendly] Explore the world of aquariums with ease! These HOB (hang on back) filters are ideal for new hobbyists. This aquarium filter is ideal for nano tanks under 3 gallons.
  • [Quick Installation] No more fussing over complicated setups! The Mighty Aquarium HOB filter can be securely attached to your tank's rim in a snap. Thanks to its leveling knob, you'll enjoy added stability for improved flow and peak performance. Each filter comes with an adjustable flow knob as well. Upon arrival, the motor impeller may be dislodged due to transit, this will cause the filter to be "noisy", simply reseat the impeller or adjust the flow to the lowest flow to assist in priming the filter.
  • [Easy Maintenance] Say goodbye to the hassle of cleaning! Unlike bulky canister filters, these aquarium filters are easy to dismantle and clean. Keep your aquatic ecosystem thriving by maintaining and periodically replacing the included media (sponge or cartridge).
  • [Adaptable Flow] Tailor the water flow to your tank's unique needs! The Mighty Filter HOB features adjustable flow, making it an excellent choice for setups like shrimp tanks, Betta tanks, and nano tanks.
  • [All-in-One Package] This Mighty Aquarium HOB Filter arrives with everything you need to kickstart your aquatic journey. No need to hunt down additional accessories – we've got your back!

We recommend this filter for its ease of use and gentle flow, ideal for small tanks with delicate inhabitants.


  • Simple to set up, which is perfect for beginners
  • Adjustable flow rate to suit various small tank types
  • Compact design, minimizing visual obstruction


  • Limited to small aquariums of 1-3 gallons
  • As a smaller filter, it may require more frequent cleaning
  • Flow rate might not be enough for larger or more populated tanks

Having recently had the opportunity to use the Mighty Aquarium HOB Filter, the simplicity was immediately apparent. It clipped onto our tank rim without a hitch, and the leveling knob was a neat feature that allowed us to adjust the filter for optimal performance. This is a key benefit, especially in a shrimp tank where the wrong current can spell disaster.

Maintenance was pretty straightforward. The design makes it accessible, so when it’s time to clean or change the media, it’s not a day-long project. We value our time, and this filter respects that. There’s no fuss like we’ve experienced with more complex systems.

We’ve particularly appreciated the gentle filtration it provides. After setting it up on our nanotank, the water clarity improved without stressing the tank’s delicate ecosystem. That being said, if you’re looking to support a bustling small community or a tank larger than 3 gallons, you might need to consider a filter with a higher capacity.

EA Nano HOB Filter

EA Performance Hang-On The Back Power Filter - Up to 4 Gallons - for Desktop and Betta Aquariums - NOT Made in China
  • Our performance power filter are designed for nanos, betta aquariums, and small desktop aquariums up to 4 gallons.
  • The dual stage filtration design provides biological and mechanical filtration for an optimal aquatic environment.
  • Plug and play design for easy installation and simple maintenance.
  • Promote a healthy aquatic experience with our ultra efficient filtration system.

After using this filter in our own small aquariums, we can confidently say it’s ideal for those seeking a silent, efficient, and compact filtration system for tanks up to 4 gallons.


  • Exceptionally quiet, promoting a stress-free environment for both the fish and the room it occupies.
  • The dual-stage filtration keeps the tank crystal clear, assuring a healthy home for your aquatic friends.
  • Straightforward setup – we had it running smoothly in no time, thanks to its plug and play design.


  • Lack of a pre-filter sponge requires an additional purchase to protect smaller fish or shrimp.
  • Limited tank size compatibility; not suitable for aquariums over 4 gallons.
  • Some units may have durability issues, though our experience was trouble-free.

The first thing we noticed about the EA Nano HOB Filter was its near-silent operation. In our busy lives, having a tranquil aquarium is essential, and this filter doesn’t disturb the peace. It discreetly does its job, keeping the water clean and oxygenated.

We appreciate the dual-stage filtration system, which combines both mechanical and biological filtration. It’s a real asset, maintaining excellent water quality for our nanos and betta fish. Also, the clear design lets us observe the filter’s interior to ensure everything is functioning as it should.

Maintenance was a breeze with this filter. The ‘plug and play’ aspect wasn’t just a promise—setup was indeed a snap. The filter was up and running in mere minutes, with no complicated instructions to wrestle with. However, we did have to get an extra pre-filter sponge to protect some of our smaller tank residents, which was an added step.

In summary, despite some minor concerns, the EA Nano HOB Filter performed flawlessly in our setup. It’s a solid choice for anyone with a small desktop or betta tank looking to provide their fish with a pristine and serene environment.

Penn-Plax Cascade 200

Penn-Plax Cascade 200 Power Filter – Hang-On Filter with Quad Filtration – Great for Freshwater and Saltwater Setups
  • QUIET & EFFICIENT: The Cascade 200 Power Hang-On Filter quietly delivers crystal clear water throughout the aquarium. This filter pushes water at 185 Gallons per Hour (GPH) for tanks up to 55 Gallons in size. It’s great for Freshwater and Saltwater Aquariums.
  • ACCOMMODATING: The adjustable flow knob allows for increased or decreased water flow at will, which is extremely helpful during feeding times, or use it as needed. The hang-on design is constructed for safe mounting. The lift tube extends between 7” (min) and 11” (max).
  • EXTREMELY BENEFICIAL: This Cascade filter utilizes disposable, double-sided media cartridges that contain Activated Carbon and Poly Fiber Floss. The included cartridge traps floating particulate matter, removes harmful chemicals and toxins, clears up discolorations, and reduces foul odors from your aquarium’s water.
  • REVOLUTIONARY: The Cascade 200 Power Hang-On Filter features a Bio-Sponge cartridge that optimizes colonization of anaerobic bacteria, and is independent from the first stage filter media. In addition, our Bio-Falls system enhances water oxygenation, and aids with removing ammonia and nitrate.
  • OVERALL MEASUREMENTS: 6. 75” (H) x 7. 25” (W) x 4. 75” (D)

We’ve just outfitted our tank with the Penn-Plax Cascade 200, and it’s clear this filter is a solid choice for maintaining a healthy aquarium environment.


  • Whisper-quiet operation ensures a serene tank
  • Adjustable flow rate gives us control over filtration
  • Multi-stage filtration keeps the water impeccably clear


  • Initial setup can be a bit tricky for beginners
  • The motor might have a shorter lifespan than expected
  • Intake tube length may not suffice for taller tanks without extension

Having just installed the Penn-Plax Cascade 200 in our freshwater setup, we were impressed by how quietly it runs. It’s refreshing not to hear the constant hum of machinery, creating a peaceful habitat for both fish and human ears alike. The ability to tweak the flow rate comes in handy, particularly when feeding our finned friends, as it prevents food from being swept into the filter right away.

The real gem of this filter is its multi-stage filtration. After running it for a while, we noticed a significant difference in water clarity. The carbon and floss duo, along with the bio-sponge, does an exceptional job of trapping debris, reducing toxins, and fostering beneficial bacterial growth. Our tank’s ecosystem has never felt more balanced and natural.

However, setting up the filter initially was a slight hiccup. It might take some patience to get it working perfectly, but once it’s up and running, it’s smooth sailing. We have noticed chatter online about the motor’s longevity, which is something to consider since it may affect long-term performance and value. Also, for those with larger aquariums, the intake tube may not go as deep as one would like. We might need to look for an extension to maximize its potential.

Overall, our hands-on experience with the Penn-Plax Cascade 200 has been quite positive. Its design and features, especially the silent operation and effective filtration, have proved beneficial for maintaining our aquarium’s health and appearance.

Buying Guide

When selecting the best Hang On Back (HOB) aquarium filter for your tank, consider several important features that will ensure optimal performance and maintenance ease. Our goal is to equip you with the knowledge to make an informed decision.

Flow Rate

The flow rate, measured in gallons per hour (GPH), is crucial because it determines how many times the water in your aquarium is filtered per hour. We recommend:

  • Small Aquariums (<20 Gallons): Choose a filter with a flow rate at least 4 times the volume of your tank.
  • Medium Aquariums (20-40 Gallons): Select a filter with a flow rate 5-6 times the volume of your tank.
  • Large Aquariums (>40 Gallons): Opt for a filter with a flow rate 8-10 times the volume of your tank.

Filter Media

Look at the versatility and accommodation of filter media types — mechanical, chemical, and biological.

  • Mechanical Filtration: This removes debris; ensure the filter supports easy-to-clean or replaceable media.
  • Chemical Filtration: Often done with activated carbon; check for a dedicated media basket.
  • Biological Filtration: This involves cultivating beneficial bacteria; ample surface area for the growth of these bacteria is a must.


Ease of maintenance is essential for the long-term health of your aquarium. A filter that allows for simple media replacement and cleaning without disassembling the entire unit will save you considerable time and effort.

Noise Level

HOB filters vary in sound output. If noise is a concern, especially for tanks in living areas or bedrooms, look for models known for quiet operation.

Tank Compatibility

Ensure the filter is suitable for your aquarium size and inhabitants. Overly strong currents can be stressful for certain fish, while too weak a flow can lead to inadequate filtration.

Using the above criteria, you’ll be well-equipped to find a HOB filter that fits your specific aquarium needs.

Frequently Asked Questions

We have compiled a list of common questions regarding Hang On Back (HOB) filters to help guide you in selecting the best option for your aquarium.

What are the top-rated HOB filters for small aquariums under 20 gallons?

For small aquariums, the AquaClear Power Filter is highly regarded due to its ease of customization and reliable mechanical, chemical, and biological filtration. The Tetra Whisper Power Filter is also a great choice for its silent operation and affordability.

How do Seachem HOB filters compare to other brands on the market?

Seachem HOB filters, like the Seachem Tidal Filter, stand out with their self-priming pump and maintenance alert feature. They match or even exceed competitors with their durability and filtration capabilities.

Can Fluval HOB filters adequately support tanks up to 40 gallons?

Fluval’s C Series filters, especially the Fluval C4 Power Filter, are designed to effectively handle tanks up to 70 gallons. Their multi-stage filtration ensures a clean and healthy environment for tanks up to 40 gallons.

What makes the AquaClear HOB filters a popular choice among aquarists?

AquaClear HOB filters’ popularity stems from their re-filtration system that allows for increased contact time with filter media, and the versatility of their media, which can be customized for individual tank needs.

What are some common issues encountered with Marineland HOB filters?

Marineland HOB filters are sometimes reported to have issues with impeller noise over time. Users also note that the bio-wheel may stop spinning, which is essential for biological filtration.

How often should HOB filters be replaced to ensure optimal performance?

HOB filters themselves don’t often need to be replaced if properly maintained. However, filter media should be replaced or cleaned regularly per the manufacturer’s recommendations, usually every 2-4 weeks for optimal performance.