Fish fade

[Daytymer]

I still have one of the notorius blue damsels that I bought to help cycle my tank. Since my tank has been cycled for over 2 years now he is at least that old. He has always been a decent tankmate and is a pretty color so he stayed. Over the past month or so, his color has started to fade. It's strange really. He is the typical blue color on his head and gills but from the middle of his body to his tail it's as though someone did a quick bleach dip on him and his blue is faded in spots, more towards the tail. He has no injuries whatsoever and is completely healthy. In fact, the only thing different about him is the color fade. Any chance it's an old age thing? Thoughts?

Tankmates:
Lunar Wrasse (if you want him and can convince my 7 yr old daughter he needs a new home, he is yours)
6 line Wrasse
Lawnmower blenny
Dragon goby
Kole Tang
Pair gold coral banded shrimp
Hermits
Margarita snails
Emerald/Rose Crabs

Corals:
Lobophyllia
Encrusting Monti
Frogspawn
Hammer coral
Mushrooms
Zoos
Xenia
Basic Anemone
Leather coral
Favia Brain
Other LPS/softies I'm sure I'm forgetting.

Water params:
Salinity: 1.025
Nitrates: .2
Ph: 8.3
Ammonia: 0
Nitrite: 0

[White Tiger]

What have you been feeding the damsel? Color changes can be caused by the food you're feeding the fish.