Discus fish have the repute of being the most flamboyant creatures among all types of aquarium fish. It is fascinating to note that these fish can change their body hue, becoming darker in color if they are stressed and more vibrant when they are content, and even ready to spawn. This Sisyphean tone modification is simply their form of exchanging aggression, or simply put their gallant display. So, if you happen to see your discus fish whose color is changing fast and appearing to be flashing like a neon sign, it might be courting or a battle for supremacy.