Aquarium filter is used for fish farming water purification device of supplemental oxygen, the aim is to: removal of feces and other contaminants in the water, keep the water clear and sufficient oxygen, no pollution, no harmful substances, suitable for the growth of fish.

Using the enclosed external filters, filter cartridges there are many filters, filter media itself has about "physical filtering", "chemical filter" and "biological filter" three functions

Physical filtering: mainly using nets, and wool, large debris removal in the water.

Chemical filters using activated carbon adsorption to remove organic matter causes muddy water and fish waste.

Bio-filtration: the use of microorganisms that multiply on filter surface, or Protozoan activity to filter and cultivate useful microbial growth, it will take some time, but also to have the right environment, effects of for better or worse, almost all depend on biological filtration capacity. To maximize the filtration function, these three functions must be a winning combination.