Fish Tank Filters: What’s the Best of 2022?

Fish Tank Filters: What’s the Best of 2020?

Do you need information about fish tank filters? Are you determined to put a small aquarium at home and do not know where to start or what tips to follow to buy the best products? You have come to the right place! Next, we present you a very complete guide to know which are the best filters for fish tanks on the market.

In this place, we will summarize the types of filters for fish tanks that exist, their operation, their cleaning method and the most effective that exist according to your fish tank. It is very important that you choose a good filter for the aquarium, since it will be in charge of eliminating waste and toxic elements that could cause health problems for your fish or plants. Do not miss this article!

The most important

  • Fish tank filters are one of the key and most important pieces of the aquarium. They are the ones that will make our fish and plants healthy.
  • In general, fish tank filters can be of two types: external aquarium filters and internal filters, depending on where the filter body is placed, whether inside or outside the aquarium. There are different models of each of them.
  • To buy the best filters for fish tanks, you must take into account factors such as the actual volume of the fish tank or the number of fish we will have and the pump flow rate of the filter. We will see it in depth in the last section, dedicated to the purchase criteria.

The best fish tank filters on the market: our favorites

Do you want your fish tank to look as bright as the first day? Are you looking to give your “little fish” a very comfortable place to live? If you want to achieve these purposes, you will require a good filter. To help you choose the best one for you, we present the best fish tank filters on the market.

  • The best internal filter for fish tanks
  • The most accessible internal fish tank filter
  • The easy to maintain fish tank filter
  • The best filter with quadruple filtration system

The best internal filter for fish tanks

Aqua Clear - Fish Tank Filter - 5 to 20 Gallons - 110v

One of the best filters for fish tanks is Aqua Clear, with capacities from 18.9 to 416 liters. It operates at a power of 110 volts. It is quick and easy to install.

It comes equipped with AquaClear foam, activated carbon and Biomax cycle protector for continuous and superior biological filtration. Its patented refiltration system allows you to control the flow without reducing its efficiency.

The most accessible internal fish tank filter

Aqueon QuietFlow 10 Aquarium Power Filter

If you are looking for economy and accessibility in price, your best option is the Aqueon filter. A product that you can buy at an estimated price of 18 USD. This kit comes in six different sizes, with various filling capacities.

Each easy-to-replace filter cartridge offers 25% more activated carbon than other brands. The item measures 16.3 x 16 x 9.7 inches. Furthermore, it is silent and its pump activates automatically after cleaning.

The easy to maintain fish tank filter

Fluval C4 Power Filter

Maintaining a filter can sound complicated, but with the Fluval C4 this won’t be a hassle. The article has five stages of filtration. Ideal for aquariums between 40 to 70 gallons.

Per hour, it manages to filter up to 264 gallons, guaranteeing you an optimal level of cleanliness and completely clear waters. Also, its operation is silent. Its dimensions are 15.2 x 21 x 21.6 inches.

The best filter with quadruple filtration system

PENN PLAX (CPF3) Cascade Hang-on Aquarium Filter With Quad Filtration System Cleans Up to 35 Gallon Tank

The Penn Plax Cascade Filter features a quadruple filtration system, which circulates up to 150 gallons of water per hour. It is suitable for aquariums from 20 to 35 gallons.

It measures 9.2 x 7.5 x 5 inches. Its internal sponge optimizes the colonization of analog bacteria, as well as eliminates ammonia and nitrites. The filter attaches without problems to the tank.

Buying Guide: What You Should Know About Fish Tank Filters

Since we are sure you have a lot of questions before choosing and buying fish tank filters, we will try to answer the most frequent ones. Remember that its main function is to simulate the recirculation of water. Otherwise, the water in a closed aquarium would remain stagnant and motionless. We start at the beginning!

What are fish tank filters and what are the advantages?

Fish tank filters are the devices that will take care of recirculating the aquarium water and keeping it clean. To do this, their job will be to filter potentially toxic chemical components that are accumulated by the biological activity of fish and plants, food or fish medications, among others. Some of its advantages are:

    • They remove impurities from the water, improving the quality of life of fish and plants.
    • They help oxygenate the water in the aquarium, as they prevent bad smells and suffocation of the fish.
    • They can generate water currents, and many species of fish love this whirlwind or rushing water sensation.
    • They are easy to clean, generally every fifteen days, and if they are properly maintained, they will last a long time.
    • You can choose between several models, external or internal, to adapt as much as possible to the size of your aquarium, its capacity and the activity of your fish.


How do fish tank filters work?

The main function of fish tank filters is purifying, they avoid the presence of elements that are suspended in the water and most of them work by hydraulic pump. The normal thing is that they consist of a water inlet, a suction pump, a chamber or basket with the filter layers and the water outlet.

In the simplest models there is no chamber or basket, and the filter materials are directly in contact with water. What is its operation?

    • The aquarium water enters the filter. It is dirty because, with the passing of days and the activity of fish and plants, it contains solid particles (food debris, plants, as well as other debris) and harmful chemicals (ammonia, nitrites).
    • It then reaches the filter head, where the water suction pump is located, and passes through the tube system.
    • Subsequently, it reaches the basket or chamber in which the different filter materials are found, of various types: the mechanical filter (which retains solid particles), the biological filter (which transforms ammonia and nitrites into nitrates) and, finally, the chemical filter (if any, which is not in all models) to obtain a better cleaning of the water.
    • Finally, when it has been purified, the clean water is returned to the aquarium.

Are internal or external fish tank filters better?

The internal or internal filters are housed inside the tank, submerged in the water of the same, leaving out the cable and its plug. On the other hand, the exteriors or exteriors are installed outside the tank. External filters are much more complete, while an internal filter is a good option, if you do not need a large filter power. In this table, you can see some of the main advantages and disadvantages of filters for external and internal tanks:


Internal fish tank filters External fish tank filters
Advantage They have a better price.
There is no danger of leakage.
Its size is small and compact.
They are silent.
They have a very high performance.
They operate at great power.
They have great capacity for filter material.
They are easy to install.
Its cleaning is simple.
It does not break the aesthetics of the fish tank.
Disadvantages Its re-circulation of water is partial.
They have a limited size.
They provide less efficient filtration.
They must be hidden so they cannot be seen.
To clean and manipulate them, you have to enter the aquarium, so we could accidentally release dirt.
There is a danger of leakage.
You have to find a place next to or under the aquarium.
Noise can generate noise.
Its price is higher.

When to use the filters for external fish tanks?

External fish tank filters are recommended for medium or large freshwater fish tanks (from 70 or 100 liters), in which we need to recirculate many liters of water or in which many fish and plants are going to live. In general, it is advisable to use them in almost any aquarium from 70 liters. They are more effective with cleaning.

When to use the filters for internal fish tanks?

If the tank is small, the internal filters will be more than enough. In very small aquariums, it is not advisable to use internal or external filters with a lot of power. The filter flow is likely to be very strong and create water currents. If we have a slightly larger aquarium, but with very few fish, internal filters are also better.

What types of filters for external and internal fish tanks are there?

Once we are clear about their main difference, and when they are recommended, we will now talk about some of the most popular filters for external and internal tanks. Next, we will introduce you to the models with some of their main characteristics so that you can distinguish them and choose the one that best suits your fish tank or aquarium:

Types of filters for internal fish tanks:

    • Sponge filter for fish tanks: It is the simplest. A foamex sponge (filter material) will perform a very basic mechanical filtration. They are used in small aquariums with quarantined fish, fry, shrimp, or a very small number of fish.
    • Box, corner or biobox filter for fish tanks: Another basic filter, but with the capacity to place more types of filter material. It is installed in a corner, fixed with glass suction cups. Ideal for small aquariums or with a very small amount of fish.
    • Internal aquarium filter : The most complete internal filter and one of the most used in home aquariums. It is very practical and quiet. It has a motor head that is responsible for circulating the water through the filter and a basket that contains all the filter material. There are models made for large aquariums up to 200 liters.
    • Plate filter for fish tank: This model of internal filter is placed under the substrate of the fish tank and is the least used because of the discomfort that this generates each time it is necessary to move or clean it. Also, the roots of the plants can collapse if they are deep.


Types of external fish tank filters:

  • Outdoor fish tank filter: Highly recommended for medium to large aquariums (from 100 to 700 liters). They need a large space in the cabinet where the fish tank is.
  • Waterfall or backpack filter for fish tank: It is an external filter for fish tank that is hanging from one of the aquarium walls on the outside, with the water absorption hose and the outlet waterfall inside. It oxygenates the water surface very well and allows the inclusion of various filter materials, but its effectiveness is not good in aquariums installed from 200 l.
  • Canister filter : This filter is 100% away from the tank. There are models of great power and with great filtering capacity.

How to clean the filters for fish tanks?

Fish tank filters require constant maintenance to remove accumulated debris and continue to function well. It is recommended to clean the internal filters every two weeks and the external filters once a month. In addition to this, there are logical warnings such as when there is a reduction in the output flow or the motor makes a lot of noise.

    • The first thing will be to disconnect them from the current and remove them from the water (internal).
    • Remove dirt and impurities without using soaps or detergents.
    • Sponges and materials are rinsed with aquarium water to avoid damaging beneficial filter bacteria, and are changed once a year.
    • If the filter has activated carbon, it must be replaced with a new one every month.

Purchase criteria

We have seen the most popular types of filters for fish tanks, external and internal, and we have answered the most frequent questions that may arise with this product. After this review, we will analyze the main purchase criteria by which you must be guided when choosing the filter that you are going to install in your fish tank. Pay attention to:

  • Fish tank volume
  • Quantity of fish
  • Filter capacity and pump flow
  • Filter materials

Fish tank volume

Fish tank filters should remove three to four times the volume of the aquarium per hour. If the quantity of fish is very large, even more. For example, in a 30-liter aquarium, the filter should have a flow rate of at least 90 to 120 liters per hour. eye! The actual volume of water in a fish tank is not that of the urn. It is the water that fits once it has been installed.

Quantity of fish

Another important factor when choosing a filter for fish tanks is to be clear about the fish population that will live in the aquarium and its type of feeding. There are foods that pollute more than others. Also if we are going to have deciduous plants, or that lose their leaves frequently. In short: the biological load that must be metabolized.

Filter capacity and pump flow

It is best to find a filter that can fit a sufficient amount of filter material to clean the tank properly, and to house the colonies of bacteria that will be part of the aquarium nitrogen cycle. This must be balanced and be proportional to the flow of the pump — that is, the amount of water and materials necessary to carry out the cleaning.

The actual filter yields are always lower than the theoretical ones offered by the manufacturer. Experts say they are about 35% lower for external filters and 15-20% for internal filters. (outstanding)


Filter materials

Filter materials are the layers of different materials that are placed, consecutively, inside the filters for fish tanks. They are responsible for cleaning dirty water by retaining solid particles or transforming harmful substances in the water before returning it clean to the aquarium.

Its volume is directly proportional to the aquarium load.

In addition, they house billions of beneficial bacteria that are responsible, for example, to convert ammonia and nitrites into nitrates. As a curious fact: for these bacteria to have a high concentration, it must take four to six weeks from the time the first fish are added to the aquarium. In these situations, the filter is said to be “mature.”

Aquarium filtration can be mechanical, biological or chemical depending on the layers of filter material that the filter carries and its proportion. This proportion will be in accordance with whether it must retain many particles in suspension (greater mechanical filtration), metabolize nitrogenous waste (biological) or condition the water (chemical).

What kinds of filter materials do each filter perform in fish tank filters?

The type of material for filtering fish tanks is key to their durability. Therefore, it is necessary that you have a clear classification, which we offer below:

  • Mechanical filtration is generally carried out by foam or foamex sponges with pores of different thickness, or by perlon wool for aquariums (much denser).
  • For biological filtration a porous material (such as clays) is used in which the beneficial bacteria live. It is usually sold in the form of ceramic beads or sintered quartz spheres.
  • Chemical filtration is not essential. The materials are activated or activated carbon, acidifying mobs or absorbent resins. It is used to change some parameter of the water, such as hardness or pH, or to remove certain elements from the water such as medicines.
  • Activated or activated carbon works like a natural sponge and gives the water a very characteristic clean appearance.


In conclusion, we will say that if you have a medium or large fish tank, it is preferable that you invest a little more in a good external fish tank filter. In addition to being easier to install and clean, it will ensure the perfect health of your fish and plants. It is better to buy a filter with greater characteristics than not to stay in the simplest ones.

Throughout the article, you will have seen that there are different types of filters for fish tanks, each with its benefits and ideal for a type of fish tank, mainly according to the size and quantity of fish that inhabit it. If you are going to start with few fish, but in the short term you want to expand the family, keep this in mind!

To finish, we would like to know your opinions, did you solve all your doubts? If so, tell us or share this article on your networks. Until next time!

Mehul D

I’m Dedhia. I’m a computer science engineer from India who lives in Boston, MA. I love dogs and cats, traveling, watching movies and listening to music. I believe it is important to maintain a healthy lifestyle by eating well and exercising regularly. I founded the website which provides pet owners with information about buying the best products for dogs and cats.