Although this may seem difficult, many top breeders have provided different information to do so. And you may find that it is easier than you may think. There are a variety of methods that breeders use to know the gender of a discus fish, most of them are used when the discus fish have already grown. To do this, a water purifier will be able to do the trick. Keep in mind that Discus Fish thrives in the Amazon River basin where the water is slightly acidic and soft. So, keep the PH level of the water lower than normal. You also need to make sure that the aquarium is away from doors that could open. This is the surest way that you will be able to get a pair of discus fish of the opposite sex. The problem here is that if you don t know how to look at a discus fish to determine the sex, you may get duped. So only go to a trusted dealer. An adult discus fish is much more expensive because you re paying for the convenience. The first thing that you have to consider is the fish tank. You need to make sure that you have the right fish tank for breeding discus fish. A 20 gallon fish tank is great for breeding as this will give you enough space for both the mating pairs to swim around and breed. 20 gallon fish tanks are perfect for 2 pairs of discus fish. Changing at least a quarter to half the water in the tank will suffice as long as you have a good biological filtration system installed. In some cases, some aquarists would just add some medication to clear up the dirt. This though should not be done often. As for their food, you should ask the store clerk what food they have been accustomed to. There are many books that can share these secrets with you and this is due to the rising popularity of the discus fish as an aquarium pet. Some people may find keeping discus fish very difficult while some find it easy, but it s all about discovering these secrets which spell the difference, and one of the biggest secrets is the environment which the discus fish lives in.