Best Filter Media For Freshwater Aquarium

Last Updated on January 13, 2022 by admins

If you want to ensure a long and healthy life for your underwater friends, these are the best filter media for a freshwater aquarium.

Every aquarium needs a quality filter media that will do its job well. There are many types of media that you can use in your aquarium to make it healthy and safe for your aquatic friends. However, choosing the right one can be tedious and confusing. That’s why we are here to help you. This is all you need to know about the best filter media for a freshwater aquarium!

Types Of Aquarium Filter Media

Every fish tank needs filtration media to clean the water. Its basic function is the elimination of fish waste, excess food, floating dirt particles from the tank water.

The filtration process is necessary for every aquarium, whether it is salt or freshwater because it ensures a healthy life for the inhabitants. Therefore, there are three main ways in which media can function to filter water from an aquarium.

Biological Media:

Biomedical or Biological Media is one of the best ways to filter aquarium water. It is basically a natural way of purifying water. The biological medium contains bacterial colonies. They consume ammonia, nitrites, and nitrates which makes your aquarium a comfortable place to live.

This medium is porous and provides a large surface area for colonies of good bacteria to multiply. The importance of Nitrification Bacteria is in reducing ammonia levels and providing nutrients to plants and animals.

These are the best bio media for freshwater aquariums:


Lava rock is an igneous rock formed by the eruption of a volcano. What makes it so special is its porosity. That’s why rocks are an excellent biological filter media. Lava rocks can grow a colony of microorganisms that can break down all the dirty, smelly elements like hydrogen sulfide in water.

Find more information about How To Prepare Lava Rock For Aquarium?

Plastic Balls

Plastic balls are designed to create good conditions for bacteria to grow and prevent clogging. Some bio balls even have small pieces of ceramic or foam that are hidden inside to attract as many bacteria as possible.

Plastic Balls

Ceramic Cell-pore

Ceramic cell-pore converts ammonia in waste into nitrite, and nitrite into nitrate. Their pore structure allows water to flow easily through a ball of Brightwater so that beneficial organisms can reproduce.

Glass Beads

Glass beads are formed by compressing very fine glass particles together. The percentage of compaction determines how porous the beads are. Due to their large surface area and structure, glass beads are used as the most common form of biological filtration. And no, you don’t have to worry, glass beads won’t break in your aquarium.

Mechanical Filter Media

Mechanical Media is the other aquarium filter media type that is the simplest one. It is also the most common form. It’s the first phase of the filtration process. Therefore, be sure to position this medium so that the water coming from the tank hits it first.

Mechanical filtration traps particles of uneaten food, food scraps, solid fish waste, decayed plant materials, and other debris. That is all substances that can cause water quality problems. Specificity is that it prevents large particles from clogging the biological medium.

These are the best mechanical filter media for freshwater aquariums:


Although in many cases they are used as a biofilter media, the sponge is more often used as a mechanical filter media. When placed in an aquarium, the sponges will increase water flow with a minimal amount of clogging. Sponges are also one of those media that give aquarium water a crystal clear appearance.


Filter Pad

Filter pads are designed to target and filter out specific chemicals such as ammonia spikes. Ammonia spikes most often occur when the balance of the aquarium is disturbed. This usually happens after moving the aquarium, a power outage, or thorough cleaning of the aquarium. Finally, filter pads are the most common type of mechanical filter medium used in aquariums.


Gravel is the main source of mechanical filtration. In addition to being mechanical, it also acts as a biological filter. The large surface area of gravel is conducive to creating a healthy environment in the aquarium as it is a suitable site for healthy bacterial colonies.

Filter Floss

The filter thread is made of a tightly bound material that captures almost all waste and contaminants. In addition to mechanically filtering detritus, it catches microscopic bubbles, responsible for cloudy water. Therefore, using filter floss media is the fastest and most efficient way to clean water.

Foam Block

The foam blocks capture large particles and debris for efficient mechanical filtration. It’s a very important part of the aquarium filtration system as it helps prevent premature clogging of other filter media.

Chemical Filter Media

Chemical media is not used as often as biological or mechanical media. However, this medium can be effective for an assortment of filtering. This filtering method is used in extreme cases. This often happens at the beginning of fish keeping when you need to boost the nitrogen cycle in your aquarium.

Chemical media absorbs toxins and removes off-odors or colors in your water. It removes dissolved particulates from the aquarium via activated carbons, resins, and other adsorbents.

The most common chemical media is using activated carbon and resins.

Activated Carbon

Carbon is very effective in removing toxins, harmful substances, and discoloration from the tank water. Be careful if you use this method while treating your fish. Namely, it absorbs or removes the chemical from the water in the tank. Therefore, you could be left without the medication you put inside. At the end of the treatment, you can return it to your aquarium to remove all leftover medications.

Learn more about: How To Make Activated Carbon For An Aquarium


Although they are less utilized than carbon, their use has become more frequent lately. They work on the principle of attracting ammonia or nitrates and/or removing dissolved organic matter. Resins are also significant for removing pollutants before they enter the nitrogen cycle.


As with everything else, you should pay special attention to the choice of filter types and filter media. Moreover, this is what will give the inhabitants of your aquarium a healthy and long life. And that’s what you’d definitely want to afford them.

What is the best filter medium for a freshwater aquarium for you? We want to hear your experiences and ideas. Let us know!

Read more about: Cleaning Aquarium Plants With Hydrogen Peroxide

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