7 Best HOB (Hang-On-Back) Filters for Small Aquariums

Best HOB Filter

HOB simply means hang on back, referring to filters that are hung on the back side of aquariums.

Well, you might be wondering why you need such a filter, especially considering that it is a bit bulky yet it hangs exposed along the tank wall.

The answer is simple. HOB filters are easily accessible as compared to other types of filters. This means that they are easy to maintain because the filtration media can be easily removed or replaced.

Therefore, if you want to have an easy time maintaining your fish tank, it is vital that you buy the best HOB filter. This article gives you an in-depth review of the best ones in the market so that you can have an easier time picking the most suitable one for your tank.

You can also read other product reviews of aquarium filter, canister filter, filter for turtle tank.

7 Best HOB Filters – Reviews

Product Name




Current Price

1. Aqua Clear HOB Filter

Aqua Clear HOB Filter

500 GPH HOB filter with an adjustable flow rate and a very large filtration compartment that house up to 6 times more media as compared to other filters


2. Marineland Penguin HOB Filter with Multi-Stage Filtration

Marineland Penguin HOB Filter with Multi-Stage Filtration

Affordable HOB filter with a bio-wheel for biological filtration as part of its 3-stage filtration system


3. Marineland 400B Pro Series HOB Filter

Marineland 400B Pro Series HOB Filter

Powerful filter with twin bio-wheels and a flow rate of 400 GPH.


4. Fluval C Series HOB Filter

Fluval C Series HOB Filter

264 GPH HOB filter with a 5-stage filtration system and can be used in both fresh and saltwater tanks.


5. Penn Plax Cascade HOB Filter

Penn Plax Cascade HOB Filter

Quiet HOB filter with a 4-stage filtration system and an adjustable flow control feature


6. Aqueon QuietFlow LED Pro HOB Filter

Aqueon QuietFlow LED Pro HOB Filter

Affordable HOB filter with an internal pump design that powers a 5-stage filtration system


7. Tetra Whisper EX Silent Multi-Stage HOB Filter

Tetra Whisper EX Silent Multi-Stage HOB Filter

An easy to maintain filter that uses large cartridges and features a time strip for reminding you of when the cartridges need replacement


1. Aqua Clear HOB Filter

Aqua Clear HOB Filter
  • Available for: 60 – 110 gallons
  • Flow rate: 500 GPH
  • Filtration stage: 3 stage

Aqua Clear’s product is one of the best HOB filters for aquariums because it has a very large filtration compartment in each of it's 5 differently sized models.

This section is big enough to house up to 6 times more media volume as compared to other filters of a similar size. This means that it can do a better job at filtration because of exposure to the extra media volume.

Additionally, the unit’s flow control is adjustable and can be reduced by up to 50% without damaging the motor or impeller. With this reduction, the water contact period with the filtration media is extended, and this ensures that the water exits in a very pure form.  

In terms of operations, the unit requires priming before use after which the pump takes over to power a 3-stage filtration system. It consists of a foam for mechanical filtration, activated carbon for chemical filtration and bio-max ceramic rings for biological filtration.

What stands out about this setup though is that it has a cycle guard system, which ensures significant amounts of beneficial bacteria remain as you change the depleted media. This is achieved by requiring only one of the three media to be changed at a time.

The carbon filter needs a replacement every month, foam filter every two months and the bio-max every three months. This arrangement ensures that beneficial bacteria are not suddenly depleted as you maintain your unit.


  • Very large filtration compartment
  • Can house up to 6 times more media volume
  • Adjustable flow control
  • 3-stage filtration system
  • Cycle guard system ensures beneficial bacteria are not fully depleted


  • Requires a lot of filtration media to fill the large media volume
  • Needs priming

2. Marineland Penguin HOB Filter with Multi-Stage Filtration

Marineland Penguin HOB Filter with Multi-Stage Filtration
  • Available for: 50 – 70 gallons
  • Flow rate: 350 GPH
  • Filtration stage: 3 stage

Marineland’s Penguin filter is the most affordable product in this review but this does not mean it is a low-quality product.

For starters, it has a 3-stage filtration system, with the revolutionary bio-wheel technology for biological filtration. This wheel is proven as one of the best methods of dealing with nitrites and toxic ammonia from the aquarium’s water.

Mechanical and biological filtration is carried out by two rite-size C filter cartridges to provide a complete water purification cycle.

Setting up the unit is quite easy. In fact, no set up is required before first use because the filter comes fully assembled. You just have to attach it to the tank wall and prime it before plugging in the power cord.

The Penguin is also easy to maintain because it requires a general clean-up and filter cartridge change approximately every month. However, it is important to maintain the same bio-wheel after this cleanup so at to reuse the beneficial bacteria that had already grown inside it.

That said, if you find this wheel broken or torn, you might have to change it and this might make you lose a lot in terms of biological filtration. The good thing though is that these bacteria grow back in a short time.


  • Affordable
  • 3 stage filtration system with a bio wheel for biological filtration
  • Easy to set up
  • Easy to maintain.
  • Bio-wheel needs no replacement unless it is damaged


  • Requires priming before use
  • Beneficial bacteria might be depleted if the bio-wheel and cartridges are changed at once

3. Marineland 400B Pro Series HOB Filter

Marineland 400B Pro Series HOB Filter
  • Available for: Up to 80 gallons
  • Flow rate: 400 GPH
  • Filtration stage: 3 stage

Marineland's 400B unit is a top-rated HOB filter because it is quite powerful, with a certified flow rate of 400 GPH and the capacity to handle up to an 80-gallon tank. With this power though, the 400B is quite expensive but it also has other features that make it worth the money.

On the inside, this unit features bio-wheel technology, which is a revolutionary design for biological filtration.

The rotating nature of the bio-wheel also promotes oxygenation of the water, which complements the waterfall design of the unit that does the aeration as the water drops down into the tank after filtration.

In terms of size, this filter is quite long and has this extended design because it houses two bio-wheels. These increase the surface area for biological filtration as well as for water aeration, making it a very powerful and effective product.

Apart from biological filtration, this unit also handles mechanical and chemical filtration by using cartridges, which are easily replaceable once they have served their purpose.

On the downside, adjustability is not featured in the 400B because the water flow is fixed at 400 GPH. However, with its powerful filtration system, there is really no need to adjust the water speed.


  • 400 GPH with the capacity to handle an 80-gallon tank
  • Bio-wheel biological filters
  • 2 bio-wheels for a more thorough purification process
  • 3 stage filtration system
  • Easy to maintain.


  • Expensive
  • Water flow is not adjustable

4. Fluval C Series HOB Filter

Fluval C Series HOB Filter
  • Available for: 40 – 70 gallons
  • Flow rate: 264 GPH
  • Filtration stage: 5 stage

Saltwater aquariums usually require more powerful filtration systems and Fluval’s C series filters are perfect for the job because they have a 5-stage filtration system, which does some thorough purification.

The first and second stages in this process do the mechanical filtration using a foam pad. A porous foam gets rid of large particles in step 1 and a dense foam captures fine debris in step 2.

Chemical filtration is done in stage 3 using an activated carbon insert, which gets rid of the bad odor, discolorations, and impurities.  

A biological bio-screen is next in line for removing any debris and spreads out the water before passing it onto the final stage, which contains beneficial bacteria in biological C-Nodes for eliminating ammonia and nitrites.

For installation, this is a clip-on filter that is very easy to hang on the tank. This also makes it easy to maintain because it can be easily unhung for cleaning or changing the filtration media.

A cleaning indicator is built into the unit to show you when the polyfoam needs to be rinsed and during this time, you should check and replace some of the other media.


  • Suitable for both freshwater and saltwater use
  • 5 stage filtration system
  • Easy to install
  • Easy to maintain
  • Cleaning indicator lets you know when the polyfoam needs cleaning


  • Relatively slow flow rate
  • Requires priming before use

5. Penn Plax Cascade HOB Filter

Penn Plax Cascade HOB Filter
  • Available for: 55 – 100 gallons
  • Flow rate: 300 GPH
  • Filtration stage: 4 stage

Penn Plax’s Cascade filter features an adjustable flow control knob that enables you to reduce or increase the filtration speed as required.

Slower flow rates are especially good for thorough water cleaning and coupled with the Cascade’s 4 stage filtration system, this results in crystal clear waters for a 55 – 100-gallon tank.

This, however, is the largest size and if you have a smaller aquarium, you should consider the smaller 20, 80, 100, 150 and 200 GPH options.

Regardless of the size, Cascades are designed to be very quiet, which means that they will not cause any interruptions to your peace after a long day at work. They also require no priming and thus, are very convenient to use as compared to other HOB filters.

When it comes to installation, this process is quite easy because the unit has very intuitive features such as an adjustable intake tube and a self-leveling case, which ensures that the filter is kept level when mounted on an aquarium wall.   

On the downside, this Cascade is relatively heavy but this is because it houses a lot of features.


  • Adjustable water-flow control
  • 4 stage filtration system
  • Available in 6 different sizes
  • Operates very quietly
  • Easy to install


  • Quite heavy

6. Aqueon QuietFlow LED Pro HOB Filter

Aqueon QuietFlow LED Pro HOB Filter
  • Available for: Up to 50 gallons
  • Flow rate: 250 GPH
  • Filtration stage: 5 stage

Aqueon’s QuietFlow is a very affordable HOB filter that has a powerful 5 stage filtration system consisting of a dense floss for mechanical filtration, activated carbon for chemical filtration and a patented bio-holster for biological filtration.

The fourth stage consists of a bio-media grid for removing any remaining toxins while also oxygenating the water and lastly, a specialty filter pad for the final water treatment. This design combines a filter and an air pump into one, making the QuietFlow a very versatile product.

In terms of design, this filter has an internal pump, which is submerged in the water when the unit is installed and operational.

This makes it very quiet with a continuous suction of water and few, if not zero, chances of leaks. Additionally, a submerged pump does not require priming on restarting the filter. 

All these features make QuietFlow one of the best hang-on-back filters available. However, the unit’s flow rate is not adjustable, instead, it is set at the most suitable speed for supporting its filtration process.


  • Affordable
  • 5 stage filtration system
  • Internal pump design does not require priming
  • Very quiet


  • Relatively slow flow rate
  • Non-adjustable flow rate

7. Tetra Whisper EX Silent Multi-Stage HOB Filter

Tetra Whisper EX Silent Multi-Stage Power Filter
  • Available for: 45 – 70 gallons
  • Flow rate: 340 GPH
  • Filtration stage: 3 stage

As the name suggests, Tetra’s Whisper filter is also a very quiet unit and this is because the motor goes into the water once the unit is installed. Water dampens the noise and vibrations and the other benefit of this design is that it does not require priming before use.

After setting off, time strip technology is used to time the carbon filtration cartridges so that you can always remember to change them before they affect the filtration process. This means that your filter will always be effective since the media “expiry” will always be in check.

The unit uses large filter cartridges and these increase the surface area for contact with the water. When the expiry date comes, maintaining the Whisper is quite easy because it has an easy access door at its top for quick changes of the filter cartridges.

In terms of size, the whisper is available in a 10 – 20, 20 – 30 and 30 – 45-gallon capacity option, in addition to this 45 – 70-gallon option. With these, you can at least get a good fit for differently sized aquariums.

However, it is important to note that this filter is not recommended for use in saltwater tanks.


  • Very quiet.
  • Does not require priming
  • Time strip technology
  • Large filter cartridges
  • Available in 4 sizes.


  • Not recommended for saltwater aquarium use

HOB vs. Canister Filters

Hang on back and canister filters are the most popular types of filtration systems used in maintaining aquariums.

HOB filters: usually cheaper and easy to use as compared to canisters but are less powerful. However, the most important differences are in the internal working mechanisms between the two.

For the filtration stages, standard floss/ foam is used for mechanical filtration while activated carbon and bio rings or wheels are used for chemical and biological filtration respectively.

The biggest issue with this design is the mechanical floss, which gets clogged up really easily and therefore, must be cleaned frequently.

Also, by being small in size and disruptive of the water surface, HOB filters allow salt to penetrate through their inner workings, which means that a bigger maintenance task is required if you use the unit on a saltwater tank.

Canister filters: on the other hand, can be quite big because they are set up outside of the tank. This means that they can house superior filtration media for the various filtration stages and at a big quantity.

These units can also be equipped with UV light for filtering out algae and other microorganisms because they can be built big to accommodate such features.

However, canister filters require more effort to maintain. First of all, they have a lot of components, which means they require more work to set up. They may also require more filtration media for replacement purposes because they are usually big in size.

Verdict: Canister filters generally are the best types but are most suitable for large tanks and work very well in purifying saltwater aquariums. However, if you have a small fish tank and you are on a budget, the best option for you is a hang on back filter.

How to Buy the Best HOB Filters

How to Buy the Best HOB Filter

1. Compatibility

A filter’s compatibility is usually considered due to many factors.

First, is the tank size. All HOB filters are rated based on the aquarium tank size that they can be comfortably used on.

For instance, a filter that is rated for a 45 – 70-gallon aquarium can be used for tanks of up to 70 gallons in capacity, although it would be too powerful for the smaller tanks.

However, the unit should not be used for any aquarium that is greater than 70 gallons in capacity because it will not be powerful enough to clean up the waters, especially if there are a lot of livestock inside.

Another important thing to consider when it comes to compatibility is salinity. There are some HOB filters that are capable of cleaning both salt and freshwater while other can only deal with freshwater.

Therefore, if you have a freshwater tank, this shouldn’t be a big worry to you because all types can purify your tank. However, the fresh and saltwater HOB filters are the best ones to buy because they will still work even if you decide to switch to saltwater fish keeping.   

2. Flow Rate

The flow rate of a filter basically shows you the speed at which the unit functions in purifying your tank’s water. The higher the flow rate, the better the filter because it can turn over the whole volume of water in the shortest time possible.

Apart from a fast flow rate, another important feature to look for is an adjustable flow control. With this, you will be able to reduce or increase the flow rate as required, giving you more control over the filtration process.

3. Filtration

Filtration is the main purpose of a filter. It is usually given in terms of stages, with stage 1 being for mechanical filtration, stage 2 for chemical filtration and stage 3 for biological filtration.

These are usually enough for the filter to be effective at maintaining your tank but they should be large enough so as to provide a big surface area for filtration.

You might notice other HOB filters having more than 3 stages of filtration and these are good for providing even better filtration so as to get clearer waters that are better for your tank’s livestock.

However, the more the stages, the more the strain that they apply to the pump. This is because the pump is left with the task of forcing water through more layers of media and a noticeable thing you will see in such systems is a relatively low flow rate due to this strain.

The result of this is high power consumption and thus, if you don’t mind paying high energy bills, a 4 or 5 stage filter is the best one for you. Otherwise, stick to the 3-stage unit.

4. Maintenance

Although maintaining HOB filters is much easier as compared to other types of filters, they still need their own form of care for instance in replacing the filtration media monthly or quarterly, depending on the manufacturer’s specifications.

Because of this, the best HOB filter for fish tanks needs to be easy to dismantle, easy to clean, easy to swap the filtration media and easy to put back together so that you can have an easier time doing this task.

5. Noise

Having been designed for indoor use, HOB filters should operate silently so as not to cause any disturbances. Ideally, such filters usually have their pumps submerged so that the noise and vibrations can be absorbed by the water.

Therefore, it is important to check for such features because the quietest unit is the best one to buy.


HOB filters are very important to have, especially if you own a small fish tank. They are affordable, yet they carry out the task of filtration really well.

After going through this article, you should be in a better position to pick the best HOB filter that can comfortably take care of your tank.