Hi, I've had my male MacMasteri for about four months. He's been relatively healthy, though about a month ago I noticed he had attached feces one day. I was alarmed but it never recurred. (I had been feeding frozen bloodworms once a week but have stopped now.) Yesterday I noticed that half of his face has darkened. The left side is dark, the right is normal. It looks like he has bilateral coloring. There doesn't seem to be consensus about what is causing it. Some say it is bacterial, other say it may have been caused by an injury. He is eating well and mostly acting normally other than that he seems to be spending a little more time in his cave. Nothing has changed in his tank. I do weekly 20% water changes with RO water. Non of his tank-mates have changed, either. No one is aggressive.