How many fish tank filter types - how they work

Fish tank filters are the most important equipment for any aquarium. Along with aquarium heaters, the fish tank filters form a system that ensure the living conditions in a tank is just right for healthy and vibrant fish. Choosing the right fish tank filters for you is also a matter of personal choice. Even though different fish tank filters work differently, they all have the same basic purpose which is to filter out debris and externals from the water which would otherwise contaminate it.




Fish tank filters generally perform one or more of the following filtration tasks: chemical, mechanical and biological.

  • Mechanical filtration removes large waste and sediments from the aquarium. All fish tank filters perform this basic but important function.
  • Chemical filtration involves the removal of toxins and dissolved matter usually through activated carbon. The porous carbon filter traps phosphates and waste in its pore. It is also able to remove ammonia and odor from the water. While it really isn’t all that important to perform chemical filtration, it can be useful especially in a tank meant for quarantine to filter out the excess chemicals used for treatment.
  • Biological filtration utilize a colony of beneficial bacteria to filter out toxins and decay from the tank. If you wish to have healthy and thriving fish, then biological filtration is an absolute must. Biological filtration is a very important filtration task.

Different Types Of Fish Tank Filters

The main filtration function performed by almost all fish tank filters are biological and mechanical. The more expensive ones add on chemical filtration as well. Your choice of aquarium filters to use should depend on the size of the tank, the quantity of fish, how sensitive the fish are, the budget you are willing to spend on the fish tank filters and finally how much time you are willing to set aside to clean it.

Here is a general look at the various types of fish tank filters being sold today:

Box Filters: Also known as Corner Filters, this is usually a clear box that contains filter floss and other media. Air is push through an air stone that in turn pumps water into the filter, through the floss and filter media which performs mechanical filtration. Over time, there will be a build up of bacterial colony providing biological filtration . Box filters are inexpensive but you should only consider them for small tanks as they are generally not that efficient. Most fish enthusiasts today also do not favor them because the box which is placed inside the tank tends does not compliment the decoration. They require weekly cleaning but are easily to clean.

Undergravel Filters: A layer of gravel sits on top of a plastic platform. By utilizing a pump, water is suck from under the gravel, forcing it to flow through the gravel which performs mechanical and eventually biological filtration . Undergravel filters usually comes together with a beginners tank that you buy in a complete set. During the weekly cleaning session, you would have to vacuum the layer of sediments that will accumulate just above the gravel.

Sponge Filter: These fairly efficient filters are usually used as a secondary filter attached to a main filter to further increase the filtration process. Sponge filters are cheap but the maintenance can be a bit messy because you’d need to remove the sponge from the tank and clean it before replacing it back again.




Power Filter (Hang-On-Back): Most fish enthusiasts use this type of filter. They are very efficient and provides a complete filtration process. Some the reasons why they are so famous is because of the mid range price, efficient filtering and simple maintenance. Just right for a mid size tank.




Canister Filter: Meant mainly for larger thanks that need a powerful filter. Though they are expensive, they do perform the best filtration process than any other filters. They require very little maintenance usually just a couple of times in a year. Also, the filter is totally out of the water so maintenance does not involve the water in the tank at all.




Think carefully about the fish tank filter that you wish to purchase because it should be an investment that is supposed to last you for many years. Selecting the right fish tank filters for you will ensure not only healthy and vibrant fish but a hobby that will be totally satisfying.