Aquarium filter media are the materials found inside an aquarium filter where water is made to pass through in order to get cleaned. These filter media are the center of aquarium filtration systems. They basically take care of the overall water quality and cleanliness of an aquarium, which in turn is vital to the health of its occupants. The filtration media achieve this by removing dirt particles and other pollutants in the water and by maintaining its nitrogen cycle.

They come in different forms and kinds but basically perform the functions previously mentioned. For classification purposes, aquarium filter media are grouped in three categories. Mechanical media removes the solid and bigger water pollutants such as dirt and particulate matter. Chemical media sucks out toxins from water through chemical means, usually using carbon. Lastly, biological media remove nitrates from organic waste by breaking down these waste materials into less harmful particles.