yellow tang, green spots

hey guys i have had my tang for about 2 years now and he has always had very small green specks in his colouring and he seems to be getting more. his health and apetite are the same and they are only noticeable on close inspection. i cant get a clear pic because his colour over powers the specs. im not sure that its anything to worry about but thought its better to be safe then sorry,
my params are
temp 26C
PH 8.4
amm 0
nitrite 0
nitrate 5ppm
phos 0.03ppm

 

A picture would greatly help...

If your yellow tang is eating healthy and swimming normally then there shouldn't be anything to worry about.

It sounds like it is either a slight colour morph, or if the green flecks are round then probably white spot or black spot.

If it's white spot then a cleaner shrimp and/or neon goby will help and providing stable ideal water qualities, you could also try isolating the affected fish and try hyposalinity.

If it is black spot then it will die off naturally, it will take quite a long time but will not spread as it needs a sea bird to finish its life cycle.

 

I wouldn't worry if the tang has had the same spots for 2 years with no ill effect.
Unfortunately I don't know what those green spots would be. Maybe you will soon have the 1st green tang- and make millions off of it! (kidding of course)