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. To go about it, there are three viable options for you, but to be honest, some of these options may not be the best way to do so. Here are your options: First, is to buy young discus fish, bout six to eight of them. As a fry, it is hard to determine the sex of the discus fish. So this is mostly a hit and miss affair. If you don t know yet how to maintain the temperature and pH levels of your tank water, then it is not recommended for you to own a discus fish yet. Try to learn more first about maintaining the livable balance of your tank water so that your investment will not go down the drain. This is why raising discus fish is not recommended for inexperienced aquarists. To maximize the surface area, a rectangular tank is usually recommended. When buying a tank, the surface area is one of the important considerations. 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. Yes they still need some looking after but not as much as compared to our canine and feline friends. This doesn t mean though that once you have your tank, filled it up with water, and purchased your feed then your all done. There are still quite a few things that you have to do to ensure that they will live a long time and save you the anxiety of having to buy new fish every time. You have to keep in mind that even if the fish heals after the treatment, the wound can leave a permanent scar, which can significantly have an effect on the overall appearance of the fish, especially on discus fish. This is why treating the wound while it s still small is highly recommended. For this kind of disease, you may want to treat the disease by increasing the water temperature from 30 degrees Celsius to 36 degrees Celsius.