So I have had 2 yellow tailed damsels for over a year since I started my tank. (i was young and stupid) but they have behaved so all was well. I got home from work late tonight and the light was off (t5) and noticed though that one of them was looking pale I pulled out the flash light and sure enough he was almost white
with a blue belly and yellow tail, the other damsel was lighter then normal but still blue. The water levels were all ok and ammonia was zero
everything else was on par with where it should be.
I know they change color based off of their mood.... is this that they are happy? and sleeping?