I am hoping someone has some information on wether this is tress related or illness. It is the only fish in the tank with any sign of anything wrong. A few days ago, I had to remove a fish because of increasing aggression, which put the tank into some stress. This fish was hiding for a couple days, but still eating. I noticed the loss of color area when it was hiding. It's overall color is a little more intense than usual, especially the black edging of the fins. Now it is out swimming and eating like normal, but the loss of color area seems slightly larger. Is this just from stress or an illness. The dorsal fin seems fine. This is a 125 gallon tank with 4 species of rainbowfish, Congo tetras, cherry barbs, 1 pearl gourami, 1 electric blue acara, 2 Bristlenose plecos and 2 corys. It has been set up for about 10 months. Ammonia 0, nitrite 0, nitrates around 10-20. Water changes weekly. Temp 75.