All you have to do is go to a pet shop and buy a breeding pair. This can set you back about 300 dollars. But you can be sure that one is a male and one is a female. If you want to save some money, but you can t really be sure tht they would breed, is to buy baby discus fish, about six to eight of them. However, before you start to attempt raising discus fish, it is important to know that discus fish can be quite hard to keep especially for people who are just starting out in this kind of hobby. You need to remember that discus fish are temperamental creatures that need special care. They are very sensitive when it comes to water quality as well as food quality. A freshwater fish, the discus comes in different vibrant colors and arrays of patterns. That s why many fresh water aquariums today have the discus fish. So if you re willing to give it a go, then you have to know first the single most important aspect in discus fish raising is the water in your tank. You have to keep in mind that unlike most freshwater aquarium fishes, discus fish needs to be taken care of properly in order for them to grow healthy and happy even if they are not in their natural habitat. These are the reasons why you need to learn about the different care tips and techniques for discus fish. It may be hard at first but as you get more experience, everything will become routine and easy to do. The aquarium size is one of the most important things that you need to consider. Discus fish thrives in deep water. So, you may want to get a large tank that is both wide and deep. Discus fish can grow up to 6 or even 7 inches. While they are still young, it is virtually impossible to determine its gender. Also, be warned that over handling the fish may result to its death. So you need to have a very keen observation so that you will be able to truly determine the sex. You will need to be very patient and to follow the fish well, for those who do not know the differences between the male and the female, it would be very hard to discover its gender.