well i'm not too sure about anything about your tank but...i have bumblebee cichlids, a red zebra, a few kennys, a blue cobalt, and even some american cichlids and convicts. i had them in a tank that had gray and white rocks. when they were in that one, the color was a lot less intense. so it might be the color of your sand or rocks, whatever you have in there. or it just might be them sleeping.