Aquarium Filter Facts

No matter what the size of your aquarium or what type of fish you keep, a filter is one of the most important pieces of equipment in your setup. Without proper filtration, contaminants in the water can quickly build up to toxic levels and harm your fish. Understanding how your tank is filtered is one way to keep your fish happy and healthy.

  1. You Can Choose from In-Tank or Hanging Filters

    • Filters come in two basic varieties -- ones that hang outside a tank and ones that remain inside a tank. Filters that remain outside a tank are more convenient, especially when it is time to change filter cartridges. But in-tank filters can create a more seamless look, as long as you are able to disguise or hide them with plants and other decorations.

    Filters House Friendly Bacteria

    • One of the most important things a filter does is serve as a home for friendly bacteria. When you set up a new tank, it goes through a cycling process during which colonies of friendly bacteria establish themselves. Those friendly bacteria break down fish waste and uneaten food, keeping the levels of contaminants in the tank low.

    Filters Come with Disposable Cartridges

    • A filter for your tank typically comes with one or two extra cartridges. The instructions on the box should indicate how often the filter should be changed. It is a good idea to purchase a box of extra cartridges when you buy a filter, which allows you to keep spare cartridges on hand if you end up changing them more often than the packaging suggests. Check the condition of the filter cartridge and replace it when it appears dirty or clogged.

    Filters Help Aerate Your Tank

    • If you choose a filter that sits inside your tank, like a box filter or a corner filter, it can do double-duty. These filters are connected to an air pump, and as the pump forces air through the filter it also helps to aerate the tank and agitate the water. This agitation of the water is important for the health of your fish and helps the filter work more efficiently as well. When water moves around in a tank, it picks up small pieces of uneaten food and other debris and sweeps them into the filter.