The tank surface area is necessary because this is where the oxygen and carbon dioxide exchanges. So if you have 3 to 4 pairs of discus fish, a 75 gallon tank would be good enough. If you can, try to add an outside filter, especially if you have a large tank, s this will be able to help out in increasing the aeration and the filtration of the tank. This will subject your discus fish with high levels of stress, which will eventually cause them to get sick. Discus fish needs clean water and good nutrition in order to thrive. When you are putting tap water in your aquarium, make sure that the water is treated first before you place the discus fish inside. However, the problem with keeping discus fish is that they are quite difficult to take care of. You see, there are several factors that you have to keep in mind when you plan on taking care of discus fish as your pet. Basically, taking care of discus fish is not that hard. Although first timers will find it difficult to care for discus fish, you will soon get the hang of it and start taking care of discus fish easily. To be honest, it s much more bothersome to be treating illness rather than just plainly keeping a routine of maintaining a clean tank, at least you can put it in your schedule. Besides, keeping your tank water clean is just one of the responsibilities of owning an aquarium. Imagine, what would life be if we don t have air to breathe? First off, you have to realize that the discus fish is not just like your ordinary goldfish, they can be quite costly and selling their fry has the possibility of making them money. You too can be able to venture in this, providing you know what you are doing. Some would say that breeding discus fish can be very difficult, well, if you make the most common, and sometimes most obvious mistakes, then you may just end up spending more and just plainly waste your time. However, you need to keep in mind that although discus fish are considered to be high maintenance fish, you will find that there are other species that can also thrive with the discus fish. And, the best thing about these fish species is that they go along with discus fish and can really enhance the look of your discus fish aquarium.