I just recently added green chromis to my tank as well, and have noticed what you are talking about on one of mine. In addition to having the "funky" spots, it has become rather lethargic, won't eat, and seems kind of listless. It won't react when I put my hand up to the glass (while the other one makes a mad dash for cover). It started off well, was a voracious eater, but now just hovers at the bottom of the tank all day and hides in the rock at night. It's not showing any other signs of disease (no white spots on the body or fins, eyes are perfectly clear, and the scales and fins appear to be normal as well - the fish isn't gasping for breath either). I've checked the pH daily (8.2), nitrite and ammonia is at 0, nitrate is about 10 ppm (working on lowering that). It's a 90 gallon tank that has been in operation for about 1 1/2 years now. Tank mates include a percula clown, a lawnmower blenny, a cleaner shrimp, and 9-gazillion baby brittle stars. Is this guy acting normal for a chromis? His not eating really worries me.