sick emperor angel, I have no idea what it is!

[hqgc]

My emperor angel is not looking very good for the last week or so and getting worse. This is what I'm seeing :
-color is way off, she is very spotty with inconsistent "patches" of white and the blues and yellows have turned very dull
-looks like the eyes are turning glazed
-fins look like they are deteriorating
Other than this her temperment and appetite is same as usual.
I just changed tanks aprox. 1 month ago, I used 50% percent of my cycled water and all the live rock and sand from the old tank.
The only problem I've been having with this tank is inconsistent temprature, it fluctuates between 76.2 and 77.7 on a daily basis. I think this is because I have the thermometer is in the return section of my sump with a fluctuating water level.
Any help with this would be great, would hate to lose this fish because she is our "prize" fish of the tank.
thanks.