Noticed just in the last day or so that my chromis is developing a slight red tint to it's back third of it's body on both sides. Also, it's always been a very active fish, he doesn't even scoot away when I feed like the Naso I have in there does and now a couple times I have seen it trying to hide. It isn't always doing it, but a lot more often than usual. It's a 180 and his only other fellow fish is the blonde naso tang. I checked parameters just yesterday before I noticed this problem and everything is where it usually is. I have a touch of nitrates which have had the whole five months it's been running and my alkalinity is a touch low but I'm not sure that would be much of a problem or not.