I have heard of people who have drift wood never have any rotting of the wood inside their tanks. That's so weird. Is drift wood so much different?I'm leaning on stress as well. My sailfin from time to time will go from jet black to like a camouflage markings that are white.
Definately pics would be great. Do you have driftwood in there for him to hide and munch?
Also..what is your lighting like?