Black Ich? or nem sting?

[Bumgrundle]

Tank: 3 months old, 90g, Blue Tang has been in for a bit over a month.
Temp-79,
Sal-49.7
Amo-0
Nitrites-0
Nitrates-10
Cal-530
Alk-172
Mag-1500
PH-8.2

It is a perfectly circular ring, no black in center. It does seem to be raised a little but hard to tell.

I know for certain this black circle was not there as of last night, and more than likely, just can't be 100%, it was not there a few hours ago when I did a water change.
She consistently is close to a BTA I have, could this be a sting? None of the other 5 fish have any marks on them.
Any help would be appreciated Thanx All!

 

[bobbravo2]

Mine had a sting like that.

 

[Bumgrundle]

Thanx for the reply mate! From what i've been hearing it is a sting and not Ich.../wipes sweat from brow. Seein' as mine is a dory, she musta forgot it stings heh

 

[Bumgrundle]

Oh and BTW: Beauty of an OST you have there. Mine is still in sub adult coloration. Looks like yours is nearing adult color, how old is it?

 

[bobbravo2]

Oh and BTW: Beauty of an OST you have there. Mine is still in sub-adult coloration. Looks like yours is nearing adult color, how old is it?

Thank you! She's a lieutenant tang, about 2-years-old. She's gotten a lot better about not getting stung. She's been sting free for 6+ months now.