You also have to remember that discus fish are social creatures. They live and travel in groups of at least 6. So, make sure that you have at least 6 discus fish swimming around in your aquarium in order to keep them happy and prevent them from getting lonely. With more discus fish in your aquarium, they will be less prone to misbehaving. 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. The big news is, most fishes, including the discus fish, maybe even more so, develop health conditions because of stress. 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. The need for a large tank is not only because they can grow big, but because they grow big fast. This means that you have to have a large aquarium in order for you to keep Discus Fish, especially if you are planning on keeping more than two. You also have to remember that if you want to keep your Discus Fish happy, you have to keep at least 6 Discus Fish together in the same aquarium. The size and shape of the fish tank is also important. The temperature of the water must be kept stable. In their natural home, discus fish usually thrives in water with temperatures between the range of 28 and 31 degrees Celsius. Any higher or lower than these temperatures will be enough to kill the fish or not let them survive for long. This is why you may want to invest in a water thermometer in order for you to constantly monitor the water so it won t exceed or drop below the required temperature. Get a couple of these fishes and they will be able to help keep your tank clean. Although Angelfish can look great with the discus fish, it is not recommended for smaller discus fish tanks. This is because Angelfish can grow very large and can bully the discus fish. They may even outcompete the discus fish for food and they may also carry diseases that the discus fish are prone to catch.