Thanks to everyone who helped give advice for the exhibit. It turned out great and I hope to post some pics soon. I recently came back from being out of the country for more than a month. Family has been helping me to take care of my tilapia but I am very concerned that I am about to lose all of them. In the past week, 4 have died. They lose a lot of their scales and turn a dark grayish color and become very lethargic. Any idea of what they could have? My tank is completely cycled.