I have a 90 gal. tank full of ciclids. One of my ciclids turned colors and its lower half is black. What causes this?? That one fish looked like it had a fungal infection,so I treated the entire tank for it and then did a water change. The fungas dissapeared, but the fish also changed colors. There is plenty of filtration in the tank. It has a corner overflow going into a wet/dry with media bags, and media balls, and a 1400gph pump. So the tank is always crystal clear. I was told that it might mean the fish is going to lay eggs. Is this true?? I dont know exactly what kind of ciclid it is?