Scrawled Cowfish Sick?

[Jukebox]

I have a Juvenile Scrawled Cowfish that seems to be losing his color on his spots and on his dorsal. This started several weeks ago and he seems to be acting normal and still full of energy but his color has not come back. When I first got him he was more green and his spots were more predominate as you can see with the two attached photos. Now alot of his spots have turned more blue and his dorsal seems to appear more transparent. I was hoping someone could offer some advice as to whether he is sick or not and or what I could do to get him better? Could this be caused by stress, the water, a parasite, Ick? He is the only fish in the tank along with several tiny crabs that do not pose a physical threat. Thank you guys for taking a look and any feedback would be great!

 

[Colin_T]

It's not a disease. I would say it is just growing and changing colour as it grows.

 

[Jukebox]

Come on guys, I need help!!!!!!!!!!!!!!

 

[Colin_T]

Do you have a protein skimmer on the tank or a wooden airstone?
There appears to be lots of fine bubbles on the fish, which isn't a major problem but does irritate fish.