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. Here are some points which can help you identify the gender of a discus fish. The hardness of the water should be between 2 and 8 and the conductivity should be around 10ms. This may be a problem if you live in a place where hard water is abundant as you will need to bring down the hardness of the water as well as the PH. A reverse osmosis filter will be able to strip everything from the water and this will also lower the PH level as well as the hardness. If the quarantined fish do not show any signs of illness after two or three weeks in the quarantine tank, you can introduce them to the main tank. Also, you should keep in mind that discus fish thrives in tropical waters. So, keep the water temperature in your tank between 84 to 86 degrees Fahrenheit. The depth and the volume of the tank will be based not only on the size of the fish, but also on the swimming habits of the discus fish. A deep tank is usually the norm, 18 inches would suffice. With the volume of water, most discus fish experts would agree that for each discus fish, 10 gallons would be necessary. If these are not available, you can buy some potted plants. These are also good places where the fish can spawn. You should also keep your tank in a quiet area in your home away from noise so as not to startle the fish. Failure to do so will stress out the fish and can cause anxiety which can lead to their early demise. This is why it is important that you monitor the water s chemistry every time you change the water in your discus fish aquarium. In most parts of the country, chlorine and chloramines are added to water supplies. And, as you can imagine, chlorine is a chemical that is not good for discus fish. Today, there are available test kits that you can use to test the water if these chemicals are present in the water and also how much of it is present in the water.