A 20 to 27 gallon aquarium would do fine. This way, you can have enough space to hold your discus fish and your aquarium ornaments and if your breeding them, future space for their spawn. Another well known secret in raising discus fish is providing them with a good diet. A good diet must be a varied diet, which can include some blood worms, beef heart, tetra pieces, and some frozen or fresh brine shrimp. 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. 3 inches would be the best size to buy them. But, the odds are that in those six to eight young discus fish, you will be able to get at least a pair or two. During spawning, you will notice that the breeding tube of the male discus fish tends to be smaller and sharper, with the female, the breeding tube will be rounder, and broader. The breeding tube can be found between the anal fin and the anus. Some breeders say that the female discus fish have a more vibrant color, but there are fewer patterns. 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 plan on buying a smaller tank know and just upgrading to a bigger one later on, you may find that this would be futile. You would just be spending more in a short period of time. A small tank will just stunt their development and will stress them out. But also remember, if the tank is too big, the young discus fish can become overly skittish and can also stunt their growth. This is highly recommended for first time owners of Discus Fish as adult Discus Fish costs lesser to maintain than juvenile ones. You need to remember that juvenile Discus Fish are far more sensitive to water quality and food quality than adult Discus Fish. You also have to know about the dealer quarantine.