9 Aquarium Filter Types for Your Fish Tank

When setting up any aquatic home for your fish pets, one of the essential factors to keep in mind is ensuring that they can survive in such home.

Indeed, spending days in finding the perfect tank and decorating it in the way you think is best can be completely wasted if you do not setup a suitable filtration system in there.

This is vitally important, as it is the only efficient way of cleaning the tank water from food debris and fish waste, as well as decomposing plant matter and other organic unwanted particles. As an ultimate advantage, using a filter will provide a safe and healthy living environment for your beloved pets.  

If you are new to the aquarists hobby, you have certainly stumbled upon so many different filter types and options, which can often lead to inexperienced keepers being confused.

To ease that out on you, today we are sharing a brief description of all the main aquarium filter types.

1. Sponge Filter

Sponge filters are one of the simplest options nowadays, as they are super-easy to install yet still effective. They are greatly suitable for smaller tanks which are not overcrowded, but they are not nearly enough strong to ensure proper filtration for massive tanks with many fish inside.

Moreover, they are often applied to temporary tanks which are used to house fish fry, as sponge variations are the safest options for such small creatures not entering inside the filter itself.

As the name suggests, sponge filters consist of a sponge filter medium, which is usually placed at one of the bottom tank corners. Polluted water passes through the medium and returns to the tank through an airlift tube.

2. Hang on Back Filter

As opposed to sponge filters which are placed on the inside parts of the tank, hang on back filters are placed on the outside, allowing much easier cleaning procedures as well as maintenance.

They are also known as power filters, and they make one of the first filter choices among modern aquarists.

They basically collect water from the tank thanks to a long siphoning tube, and they then push such water through a series of multiple medias, returning clean water back to the tank.

They are quite effective in their tasks, but they are impeller powered, meaning that they can sometimes cause quite noisy vibrations while working.

3. Underwater Filter

Underwater filters are basically a synonym for internal filters, which are characterized mainly by being placed inside the tank, under the water surface. Remarkably similar to sponge filters, but slightly more complex.

Contaminated water enters the filter box, passes through a filter medium, and then exits through the airlift tube in order to return to the fish tank in a cleaner state.

Underwater filters are ideal for smaller tanks, but they should be avoided for those fish which are extremely sensitive to water flow, such as betta fish.

4. Overhead Filter

Overhead filters present a handy combination of external and internal filters. The filter itself is installed at the top of the tank, above the water surface. The tube which will collect water is placed just below the water surface.

They are very practical as they allow extra space for basically any kind of filter media, as well as a super-easy maintenance and cleaning without bothering the tank inhabitants. Moreover, most overhead filters do not have to even be turned off while being handled.

5. Canister Filter

Canister filters are one of the top choices among aquarium keepers which have either massive tank sizes or extremely sensitive fish to care about. They are external filters which are sealed and fully flooded on the inside, providing continuous and superb filtration activities.

In order for your canister filter to work properly, you should setup an intake pipe on the inner side of the aquarium. This will allow for dirty water to be flushed through the canister, which can be filled with various filter materials. Next, water returns to the tank through a second, exit pipe.

The top of the canister should be equipped with a suitable water pump, to allow fluid filtration activities without the risk of collecting too much water from the aquarium at once.

Filters like these are extremely strong and functional, and often chosen for high maintenance or large tanks. However, they come with their own maintenance requirements, as well as higher costs.

6. Undergravel Filter

These can be either used in a combo variation with canister filters to ensure double filtrations, or independently. However, they are rarely used as an independent filtration option nowadays, as they are a quite old method which certainly has many improvements in modern filter types. Therefore, these are probably among the less applied filters to aquariums todays.

The basic principle of undergravel filters is using the existing gravel as a sort of a filter media. Indeed, gravel does feature beneficial bacteria among it, so it can be used for such purposes, but it is probably not enough for any more demanding size or type of aquarium.

Such filter consists of a porous plate which is placed below the gravel substrate, but such substrate needs to be evenly setup as well as free of any sand or peat particles, to avoid the filter getting blocked.

Additionally, they can become harmful to live aquarium plants over time. All in all, these probably offer more disadvantages than positive sides, unless they are used as an addition to canister filters.

7. Surface Skimmer

Surface skimmers are greatly useful for two main reasons. First of all, they are super-easy to install. And secondly, they are actually able of removing the debris and waste before they even start decomposing.

There are more types of surface skimmers available, and they mostly depend on the method of attachment to tanks, as well as on the basic way of performance. Therefore, you may often find yourself choosing between three main kinds: air-driven, turbo and venturi skimmers.

The principal difference is focused on how they manage to mix water and air in order to obtain bubbles. The more bubbles there are, the more efficient will the skimmer be. Indeed, surface bubbles attract waste particles and then collect them into a container, which is always placed outside the tank.

8. Sump Filter

Some keepers love setting up a sump filter in order to keep their aquariums neat and much tidier. In fact, the sump is not a real filter per se, but it is more of a container which allows for great maintenance and doubles as a filter.

The sump it usually setup just below the aquarium containing fish, and doubles both as a filter as well as a storing area for tank utilities and equipment. Such setup allows for aquarium water to actually increase.

Consequentially, this lowers the possibility of such water becoming dangerous by having increased ammonia or nitrate levels, as well as the chance of having any other fluctuations or spikes, such as those in pH levels.

On top of that, the constant fluctuation of the water between the actual aquarium and the sump can lead to water aeration generally improving.

9. Wet / Dry Filter

Intricately linked to the sump, a wet/dry filter is usually placed below the tank (although there are some less popular versions of it being placed at the tank top). That way, polluted tank water can simply head to the bottom thanks to gravity.

Next, water heads to a pre-filtration activity which can be obtained by setting some wool resting on the perforated plate. Such pre-filtered water should now rain down through a filter medium. From here, water flows all the way down to the sump.

And finally, such sump can contain either multiple types of filtration medias or act as a container for heaters, thermostats, and other equipment.

Wet/dry filters can basically be considered as an alternative to canister filters, as they too are extraordinarily strong and perfectly suitable for large tanks or tanks with super-sensitive fish.

They are often used in reef tanks and the filter media can be adjusted to your aquarium predispositions and necessities.

Wrapping Up

Filters are one of the most important parts of any aquarium, both marine and freshwater. They are basically the only efficient way of ensuring that your beloved fish pets are provided with a safe and healthy living environment during their life in captivity. One could say, this is the least that humans can do for them.

And even though some super-small tanks such as 5 gallons can function well with no filter, this has two sides. Indeed, with smaller tanks with no filter, you would be required to perform much more frequent water changes to ensure your fish are getting the basic breathing predispositions.

Consequentially, this can bring more harm than benefits, as such small tanks are extremely difficult to maintain stable and safe. Therefore, a filter is always recommended, even for small aquariums. And that is exactly why there are so many types for you to choose from.

Fishkeeping   Updated: July 1, 2021
avatar Hey, I'm Fabian, chief editor at Aquarium Nexus. I really enjoy the aquarium hobby and love sharing my experience with others. If you have any questions feel free to contact me or leave a comment below.

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