Because of the large quantity of 'after-breeding', the keeping of this fish has become increasingly easier. Besides, the development of the technique has improved. This means that several sorts of equipment, such as osmosis apparatus and UV-Lamps, can easier be purchased for the "aquarianist" and are much handier and saver in use. At every aquarium shop you can get a large variation of (frozen) foods of high quality.
We have to take into account that we are dealing with a sensitive and rather large fish species. For instance an adult discus has to use about 50 liters of water. In case of four discus fish, you have to have a tank containing minimal 200 liters.
The aquarium has to have a powerful filtration system, because of the large waste production. A good filtration anyway never acquits the owner of his duty to take care of a very good and intensive water refreshing.
The best water refreshers are the Asians. They refresh the total tank every day with fresh water. A rule of thumb is a daily refreshing of at least 30 % of the water.
You have to take care of the heating as well (minimum 28 degrees centigrade required). I am an advocate of the double thermostat system, to prevent our 'precious jewelry' from getting cooked.

Water for just keeping Discus fish need not be as soft as that required for breeding purposes. Water of between six and twelve degrees general hardness will suffice. This will provide more stable water conditions and provide your Discus with minerals they need for growth and vitality.

As long as the pH is on the acid side of neutral, between pH 6.0 and pH 7.0, your Discus will be quite happy.

High ammonia and nitrite levels are not acceptable. These must be maintained at 0. Keep an eye on these levels when adding new fish to your aquarium whilst the biological capacity of the filter catches up with the increased load. Nitrite levels should also be kept as low as possible. This can be achieve by frequent partial water changes and or encouraging good plant growth.

If algae becomes a problem in the aquarium it is worthwhile testing for phosphate. High phosphate levels can again be reduced with partial water changes, assuming that the replacement water is phosphate free. Otherwise a proprietary media like Rowaphos, placed in the filter, will remove the excess.

An heavy metal filter, (sometimes called metalex) which consists of a pre filter pod, carbon block pod and a CBR2 pod will remove almost all compounds that will harm your Discus fish. It will not however remove general hardness.

Hence if you live in an area with tap water which as a general hardness of over twelve degrees, a reverse osmosis unit would be a better purchase. This will provide pure water which is much easier to adjust to the desired levels, both for keeping or breeding Discus. Both units will require periodic replacement of the cartridges. How frequently the cartridges will need replacing depends on the levels of the compounds being removed from the tap water.