Best Hang On Back Filter for All Aquarium Sizes

Cleaning your fish tank is an essential part of being a fish owner. Not only is it unpleasant for your fish to live in dirty water, but it can also be extremely harmful to their health and wellbeing.

As well as not being good for your fish, a dirty tank can also look extremely unpleasant within your home, so regular cleaning is necessary.

Manually cleaning your fish tank can be tedious, so hang on back tank filters have become so popular in recent years.

With that in mind, we’ve put together this helpful guide to the best hang on back filter for your fish tank.

It’s full of all the information you could ever need to ensure you buy the best filter for your fish.

In a hurry?

If you need a hang on back filter for your fish tank quickly, we would recommend the Penn-Plax Cascade Hang-on filter.

This filter is excellent value for money and comes packed with great features which we believe make it the best on the market, including:

  • It delivers up to 300 gallons of crystal clear water every hour when used in a 55-100 gallon fish tank.
  • It comes with a bio-falls quad-filtration system which provides filtration to remove anaerobic bacteria and chemicals including ammonia and nitrates.
  • The device comes with an adjustable flow knob which allows you to reduce filtration when feeding and in other situations when necessary.
  • It is suitable for use with both freshwater and saltwater fish.


Penn-Plax Cascade Hang On Filter

Penn Plax Cascade Hang-on Aquarium Filter With Quad Filtration System Cleans Up to 100 Gallon Tank (CPF5),Cascade 300

Our favorite hang on back filter on the market is the Penn-Plax Cascade Hang On Filter. This device is packed full of wonderful features which make it an excellent choice for keeping your fish tank clean.

It is suitable for use in large fish tanks, including fish tanks that hold between 55 and 100 gallons of water.

In a tank of this size, the filter system can deliver up to 300 gallons of crystal clear water every single hour it is in use, ensuring your tank always remains clean.

As well as being suitable in large tanks, this device is also suitable for both freshwater and saltwater fish making it a great option no matter what type your fish subscribe to.

Any fish owner will know how frustrating it is when you cannot adjust the filtration of the system when you want to feed your fish.

Fish food is not cheap, and it is essential for your fish to remain healthy, so the last thing you want is for your filtration system to suck up your fish’s food.

There’s no need to worry about this device because it comes with an adjustable knob allowing you to reduce filtration pressure when feeding your fish.

Additionally, the system comes with bio-falls quad-filtration to remove anaerobic bacteria as well as harmful chemicals and contaminants including ammonia and nitrates.

With all this considered, it’s clear that this is one of the best options on the market.


  • Delivers up to 300 gallons of crystal clear water per hour
  • Suitable for use in 55-100 gallon fish tanks
  • Bio-falls quad-filtration system provides efficient filtration to remove anaerobic bacteria and nitrate and ammonia removal
  • Includes a carbon cartridge to remove harmful chemicals and contaminants
  • Adjustable flow knob to reduce filtration when feeding
  • Suitable for both fresh and saltwater fish


  • No notable drawbacks


Aqua Clear Fish Tank Filter 5-20 Gallons

AquaClear, Fish Tank Filter, 5 to 20 Gallons, 110v, A595

We also love the Aqua Clear Fish Tank Filter designed for 5-20 gallon tanks.

While the first option that we’ve looked at is designed for use with large tanks, the Aqua Clear fish tank filter is better suited for smaller tanks.

This specific model by Aqua Clear is designed for use in tanks of up to 20 gallons, however, it is available in a different model for larger size tanks.

Just like all of the other filters on this list, this model by Aqua Clear is designed to hang onto the side of your fish tank allowing for quick and easy installation.

This model by Aqua Clear is designed with all of the company’s best equipment for excellent filtration.

This includes Aqua Clear foam, activated Carbon Filter, and BioMax cycle guard for superior water quality. Additionally, the device filters in 3 different levels: mechanical, chemical, and biological.

This increases the chance of pure water in your fish tank and ensures that the water is always clean and healthy for your fish.

While this device will continue to operate constantly, if you want the filter to work at its most efficient level you should clean it once every 2 weeks.

With all of this considered and the device’s energy-efficient pump for low operating costs, there’s no doubt that this is one of the best options available.


  • Quick and easy installation
  • Provides both mechanical and chemical filtration, as well as biological filtration
  • Equipped with the best Aquaclear equipment for optimal filtration
  • Suitable for use in tanks up to 20 gallons.
  • Clean every 2 weeks for maximum efficiency
  • Energy-efficient pump lowers operating costs


  • No notable drawbacks


GRECH CBG-800 Hang On Back Filter

GRECH CBG-800 5W UV Sterilizer Hang-On Back Filter, 20-50 gallon/211 GPH, Black

You should also consider the GRECH CBG-800 Hang-on Back Filter. Of all the options that we have looked at on this list, this is the only one that features a UV lamp as part of the filtration process.

That is because this device is not just a filter, it is also a sterilizer so it contains a 5W UV sterilizer lamp which eliminates algae and bacteria from the water of your fish tank.

Additionally, this device also comes with a surface skimmer as part of the filtration system which removes unwanted contaminants from the surface of the water in the tank.

This filter is suitable for use in any fish tank that contains between 20 and 50 gallons of water and is not designed for specific use with any type of fish.

As well as its sterilizing and skimming features, this device also comes with a dual-level filtration system, filtering both mechanically and biologically. Just like all of the other models on this list it is easy to install thanks to its hang on back design.

But our favorite feature of this device is its silent operating noise. If you keep your fish tank in your bedroom, or you have thin walls in your home, this is an excellent option for you.

The majority of fish tank filters are loud when operating, however, this device produces a very minimal amount of noise, allowing you to sleep peacefully while the filter cleans your tank.

With all of this in mind, it’s clear that this is one of the best options available.


  • Adjustable 211gph filter flow rate with surface skimmer
  • 5W UV sterilizer helps eliminate algae and bacteria
  • Suitable for 20-50 gallon tanks
  • Mechanical and Biological filtration system
  • Simple installation with hang on back design
  • Silent operation ensures minimal noise while the filtration system cleans the tank


  • Difficult to disassemble for cleaning

Best Hang On Back Filter Buying Guide

If you still aren’t sure which hang on back filter to buy, we’ve added this buyer’s guide which is full of all the information you need to know about these devices.

So let’s take a look at all the different things you should consider before you buy a hang on back filter.

Tank Size

The main thing that you need to consider when buying a tank filter is the size of your fish tank. The majority of fish tank filters, especially hang on back filters, are designed for smaller tanks – like filters for 10 gallon tanks.

While you can use a hang on back filter for a larger tank, it might prove ineffective as the filter is unable to clean enough water per hour to keep the tank clean.

There are some tank filters that are designed for larger tanks, and these often have extra levels of filtration added to the design.

They often include biological compounds or natural sponge as an additional filter to increase the efficiency of the filter in the tank.

Noise Output

You also need to consider the level of noise that is output by the device. In general, hang on back filters are loud when they are in use.

This is not exclusive to hang on back filters, generally, all filters will be noisy when they are operating.

While this will not be an issue if you keep your fish tank in the kitchen, but if you keep the tank in your bedroom, a noisy filtration system could keep you up at night.

You also want to consider this if you are keeping a fish tank in your living room, as a noisy filter could interrupt your day to day life.

So if you are going to keep your fish tank in an area of the house where noise will be an important consideration, you should look for a hang on back filter that is advertised as having low operating noise.

Purchasing the Right Filter for your Fish

There are a variety of different filters available, and there are some makes and models which are tailored specifically to a certain breed of fish.

Similarly, some tank filters will be designed for use with either saltwater or freshwater fish exclusively.

Due to this, you must check that the filter you are looking at is suitable for use with your type of fish before you make a purchase.

However, some hang on back filters will be suitable for use with all types of fish, and even with other types of aquatic animals, including turtles.

So it is very important that you do your research before you make a purchase.

Frequently Asked Questions

How do you set up a hang on back filter?

Of all the fish tank filters that you need to set up, a hang on back filter is probably the easiest. Some hang on back filters will come ready constructed for use, while others will require some minimal set up before you can add it to your tank.

Different filters will require a different setup process, and the majority will come with instructions on how you set up the device.

Once the filter is constructed, you can then attach it to your tank by hanging it onto the side of it.

However, the majority of filters will require at least 24 hours to clean the water before you can add your fish so you must check the instructions before installing the filter and adding your fish to the tank.

Is it okay to turn off a fish filter at night?

Fish tank filters can be noisy so understandably, it can be tempting to switch the filter off at night. Especially if the fish tank is in your bedroom.

However, you should not do this. The filter plays a key role in the health of your fish tank and the fish that live inside of it.

By shutting the filter off, you prevent it from cleaning the tank which can allow bacteria to grow within the tank.

Some fish are extremely sensitive to changes in the environment so simply switching off the filter could damage their health, and that’s without considering the risk of bacteria in the water.

So for your fish to remain in good health, you should not switch off your fish tank at night.

Can a fish tank have too much filtration?

There is such a thing as over-filtering a fish tank, however, it is incredibly difficult to do.

It is much more likely for you to under-filter your fish tank.

This is especially easy if you have a small fish tank containing lots of fish, as they will produce more waste and it will put more stress on your filtration system.

To avoid this, if you have a large amount of fish, it is a good idea to install multiple filtration systems to ensure that the water is always clean and healthy for your fish.

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