Blue face angel colour loss

Question
Hi there i have a blue face angel in my tank that's been in for nearly two weeks with no problems until now, he is housed with 5 yellow tail damsels, pink spot goby, magenta dotty and a lemonpeel angel. the tank is 400 litres with good protein skimmer, filtration, oxygen etc.  I noticed yesterday that he had a small patch of colour loss on his face and this morning when i got up it has spread to a few varied size patches over his body, do you think it is lateral disease or something else, i have observed the tank and there is no bullying going on between any of the fish in my set up, i have recently done a large water change in the tank and my levels seem to be fine, do you think it could be stress as he is the newest member. All my other fish are fine with no signs of illness. any info on how to treat this or ideas on what it could be would be appreciated. many thanks Si

Answer
Hello Simon,

I am so sorry for the delay.  Your question got routed into the question pool, and i guess i didnt check it like i should have

As to the condition of your angel... ARe you feeding him well.  Lots of vegetables.  NORI/Seaweed??  Even broclin or cauliflower.

If not, I am not sure what it could be.  I guess you could treat on a prevatative measure and use some MELAFIX, but that is like treating a common cold with antibiotics, no  melafix is not an antibiotic, but, i just dont like treating something and not knowing what it is..

Anyways, try giving him better foods and see what happens and please let me know

thanks

bill