discus fish

Discus Fish Tank Filters

Good biological filtration is absolutely required, with complete, but not overly brisk circulation, to ensure all the water and wastes are being swept up and passed through the filter. Discus are highly sensitive to ammonia and nitrites and the substantial accumulation of nitrates. Because of this, you need to be diligent about water testing, regular water changes, and caring for your biological filter media.

Before placing your discus into an aquarium, make sure the system has been thoroughly cycled. For best results, your tank should show no signs of nitrite and accumulated nitrates for two weeks or more before introduction of the fish.

Most aquarium filters can be used for your discus tank. However, they must be properly configured for your tank. The first step in this configuration is to understand the types of filters available. There are three types of filter categories and they are based on the filter's function.

Chemical Filters Chemical filters use carbon, resins, or other chemicals. This is NOT a good filter for a discus tank because the chemicals hold impurities in the tank that water changes would otherwise eliminate. This could cause impurities to leach back into the water.

Mechanical Filters Mechanical filtration collects debris that is removed at a later time. A pad is usually used to gather the debris and it can be rinsed periodically to clean it. This type of filter is rarely needed in a discus tank, however, because maintenance and regular water changes usually take care of removing debris.

Biological Filters Biological filtration is the most important filtration method in any aquarium, especially the discus aquarium. For filtering a discus tank, a very porous biological filter media should be used. This type of media will allow plenty of good nitrifying bacteria to colonize it, which will make it very effective in removing toxins and impurities.

There are several styles of biological filters. The following paragraphs detail the types of filters and their basic usefulness in the discus aquarium.

  • Sponge Filters
  • Sponge filters are really best for small tanks (20 gallons or less), but they can also be used in larger tanks, as long as you use multiple filters. They are simple filters--cheap and simply designed. They connect to an aquarium pump by a tube. The sponge is a breeding ground for bacteria, however, so have to be careful that smaller fish do not get caught underneath the sponge!

  • Under Gravel Filter
  • For a long time the under-gravel filter (UGF) was the most popular type of filtration found in aquariums. This, however, this is not a good filter choice for a discus aquarium because the decomposing material builds up under the filter plates and it is not possible to properly clean the gravel without disrupting the nitrifying bacteria. If there are no filter plates under your gravel it is much easier to perform aggressive cleaning of the gravel, thereby removing more debris.

  • Canister Filter, Fluidized Bed Filter
  • These types of filters create a closed system that increases the oxygen demand on the tank. These filters actually compete with the discus for oxygen! Also, if these filters fail, deadly toxins are created very quickly because of the closed system. If you decide to run a canister filter as your filtration method for your discus tank, you should have a strong aeration system to keep an adequate level of dissolved oxygen in the water.

  • Hang On Power Filter
  • This type of filter is an excellent filter to use for your discus aquarium, if it is properly configured. The filter needs to be filled with biological media, but they usually come with a sponge or a plastic grid. The plastic grid is not ideal for filtering bacteria and some sponge material is too coarse for proper nitrifying bacterial growth. When you use this filter, make sure you use a good biological media.

  • Wet Dry Filter (Trickly Filter)
  • Although these types of filters can be good filters for a discus aquarium, some caution needs to be used. They are excellent at degassing carbon dioxide and oxygenation, but to be effective for discus, the biological media should be placed in the webbed, submerged portion of the filter that is under the plastic bio balls. The media used should be porous and the best media is the type that is sold for canister filters.