Fish Tank Care Guide

Fish Tank Care Guide - All care guide for fish and fish tank maintenance for hobbyists

How to choose an aquarium filter for your fish tank?

The aquarium filter plays a critical role in maintaining the overall health of your aquarium. The main function of any best aquarium filter system is as follows:

  • It promotes the fish tank nitrogen cycle by providing a medium for the growth of bacteria.
  • It removes waste and debris from the water.
  • It aerates the aquarium’s water. Through this process oxygen is added to the water and CO2 is removed.

There are three types of filtration systems and whatever aquarium filter type you select must incorporate all three. There is mechanical filtration which removes solid wastes suspended in the water by passing it over material that screens the small particles out. The filtration medium over time will become covered with beneficial bacteria. This will allow it to perform biological filtration as well.


The purpose of biological filtration is to change harmful ammonia into nitrates and then nitrites. This process is known as detoxification. Finally, chemical filtration is what helps keep your aquarium water clean and sparkling. Chemicals and dissolved minerals are absorbed as the water passes over filtration mediums such as activated charcoal.

Popular mechanical filters come in three general types. A canister filter provides chemical biological, chemical and mechanical filtration and is very popular among hobbyists. They are capable of turning over several hundred gallons of water per hour. For this reason they are often used on larger aquarium systems.

Power filters can also function as mechanical, biological and chemical filters. They run on electricity and generally hang on the outside of the aquarium. They come in a variety of sizes so they will handle different size tanks.

You may also want to consider corner filters. These are submersible filters that function primarily as mechanical filters. These filters have been around a long time and have evolved a lot over the years. They are still very popular among aquarium enthusiasts.

A good aquarium filter will cycle your aquariums water completely at least eight times per hour. Most good mechanical filters are rated by the number of gallons of water that flow through them every hour. Check the filter box. It should be labeled with the GPH rating. It may also show the size tank the filter was designed for.

If you have a tank larger than ten gallons, you might want to have two aquarium filters. You may want more than one filter even if one will handle your entire aquarium’s requirements. It’s always good to have a backup filter in case one fails. You can mix and match the filters any way you want. You could have two power filters or one canister and one corner filter. It won’t matter.

Here’s another consideration on aquarium filter choice. Filters that allow you to replace one part without having to throw out everything and lose the whole bacteria colony are a better way to go. Most good filters will tell you which parts you need to replace and when to replace them. This will protect the bacteria buildup that helps keep the water and your fish healthy.