Question from Shafaq: I want to know more about the difference in sex of discus in detail. How to differentiate them on sight? Determining the sex differences of Discus just by looking at them is nearly impossible unless you are witnessing a spawning pair. Unfortunately the most accurate way to determine gender is when they are forming pairs and actually breeding. However, there are some theories out there that suggest the males are usually bigger and more colorful than females from the same spawn. If you are trying to get pairs, a good approach is to buy 6 or 8 Discus and hopefully the odds of getting a pair will play into your favor.