For discus, there are 2 considerations in tanks: depth and volume of the tank. Due to their size and swimming habits, a minimum of 18″ is needed for tank depth, the deeper the better. Regarding volume, a good rule of thumb is that each adult discus will need 10 gallons of water. Tanks larger ones will also give more stable water conditions, and taking into account other considerations, the minimum size for a discus display tank should not be less than 55 gallons.It is also advisable to use a rectangular tank.Not only are they cheaper, but which are more efficient as they maximize surface area.Surface area is the most important factor when purchasing a tank.Why?Because it is only on the surface of the tank that gas exchange occurs.(Oxygen in, oxygen out carbon dioxide)., and your biological filter works as required, up to twenty 3-inch-sized young fish, or 6 or 8 fully grown discus can comfortably inhabit the tank.A fil can be added external to large tanks to increase basic aeration and biological filtration needs. .

Keep in mind that when young discus are small, they grow rapidly and become quite large in a short period of time if they are fed well and the water quality is maintained. If your tank is too small they will not be happy and you will quickly stunt their growth. Juvenile Discus should not be kept in tanks that are too large. Being a social fish, Discus tend to become very skittish in large tanks. At our hatchery we put 6 discus up to 1.5″ in a 29 gallon tank. They will move to larger tanks when they get to 2.5″ and show possible signs of “mating”. Always try to buy the largest tank you can afford for discus.

If breeding Discus is considered later, the tanks can be reduced to twenty gallons per pair. At our hatchery, 29-gallon rectangular glass tanks are used for each breeding pair.

To begin the process, a bare bottom tank with 2 ½ gallons of water per inch of fish, a pair of sponge filters, and a cartridge filter with activated carbon are used. This is kept at 6.6 – 6.8 PH, and the temperature is set at 82 – 84 degrees F. We do 50% water changes weekly, and some breeders go as high as 95%. Optimum results would be achieved with a 15% daily water change. Because the discs produce slime on their body and shed regularly, they coat the inner surface of the tank and promote bacterial growth. A safe bet is to clean all the disk tanks every week. Commercial sponges and brushes are available to do this task.

Because discus are large fish, they require clean water and proper filtration. The tank must be “cycled” and tested for nitrates/nitrites before placing Discus in the tank. Our policy is to use fish such as some of the more common cichlids to “cycle” the tank. A good rule of thumb here is to wait at least 4 weeks before attempting to set Discus with the “cyclist” fish. If you’re an active member of the aquarist community, a friend may lend you some “cycler fish” to start your project, and the “cyclers” can be returned to their owner upon completion of the cycle.

Discus prefer soft water, due to constant rainfall and runoff in their natural habitat. However, we are more concerned with cleanliness. High quality tank hygiene is far better than optimal water conditions, although we strive for both. Discus will adapt to most conditions, including PH up to 7.8 and microsiemens hardness to 350 ppm, but cannot survive in constantly changing or dirty water conditions.