Good filtration is the prime priority in the discus tank. Basically, there are three types of filtration - mechanical, chemical and biological. Let's start with the basics...

Mechanical filtration removes the uneaten food, waste products and acumulated plant waste from the tank. Different methods will accomplish this - pads, sponges, and floss, to name a few. The objective here is to capture the dirt before it pollutes the tank to high levels. Common filter floss is inexpensive, and highly efficient, making it a good medium for the tank filter. One must keep in mind, however, that the function of the mechanical filter is basically aesthetic.

Filtering using chemical filtration takes place at the molecular level. The most commonly used medium is activated charcoal. Activated charcoal adsorbs a huge amount of pollutants in the tank, and discoloration, antimony, arsenic, chlorine, chloramine, chromium, hydrogen peroxide, potassium permanganate, phosphate plus some of the heavy metals and other toxins in different degrees. (adsorbs: Formation of a thin film on a surface.) It does not, however, remove ammonia, nitrite or nitrate, so don't expect it to do the job of biological or mechanical filtration. If your tap water is overly high in phosphates or nitrates, there is the chance that your fish won't do well until you pretreat the water with activated charcoal or other specific resins. If you live in the city, chances are good that the city can provide you with an analysis of their provided water. If, however, you live in the country, and have your own well, then the water should be sent to a lab for testing.

Activated charcoal can produce crystal-clear water, but the downside of this is that one tends to rely on the activated charcoal to cover up sloppy maintenance. It should be used as a back up only, and you should not be dependent on activated charcoal to keep water safe and clean for the Discus. Frequent water change is the only real insurance you have of keeping your Discus safe and in good health.

I have saved biofiltration for last because it is the most important aspect of a good environment for Discus. Without good biofiltration practices, your Discus will not survive. Mechanical and chemical filtration results can be seen visibly - the tank just looks cleaner. Even though chemical filtration does remove some of the toxic materials from the water, it takes biofiltration to make the water safe for habitation.

Cycling a tank is a practice that reproduces the nitrogen cycle in the aquarium. In the aquarium, we need beneficial bacteria, which are known as nitrobacters. (Proline Bacteria is a well known brand of bacteria strain used in aquaria. A kit for starting the normal freshwater tank is a little over $9.00.) These "good" bacteria colonize the filter media and every surface of the tank. The most beneficial of these bacteria is Nitrosomonas sp. which consumes the toxic ammonia that is produced by decomposition of fish waste, plant matter, and uneaten food. In the Nitrogen Cycle, the ammonia is reduced to nitrite. The nitrite is then consumed by Nitrobacter sp. and is reduced to nitrate, which is the least toxic end-product of nitrification. The nitrate is then removed from you system by a regular water-change regimen.

Maintaining a healthy bacterial colony in the biological part of your filtration system is quite simple if care is taken to not destroy the colony. When cleaning the media, use only tank water. Never use hot water or fresh tap water to clean the sponges or media, but instead gently rinse and carefully wring out excess water in a pail of tank water. The goal here is to maintain the highest rate of bacteria as possible on the media.

It is possible that your biological filter will crash if the aquarium is left without power for a day. The bacteria are without oxygen for a period of time which will cause them to die, your fish will be gasping for breath, and a foul smell is encountered in the tank. Never simply turn the filter back on! this will flood the aquarium with toxins, and the media must be replaced if a crash occurs.

Following these simple principles will help to insure that your Discus have a happy and safe environment for many years. Again, there is no subistitue for regular water changes, but by following these simple rules, chances of survivial of the Discus are much higher.