Blue Tang Black ich? or maybe....

[Bumgrundle]

....a nem strike? (I hope) 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 an hour 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!

 

[Bumgrundle]

A Slightly better pic....

 

[Humblefish]

It's too large of a spot to be black ich. A nem/coral sting is very possible though.

Sal-49.7

This can't be right, as it should be closer to 35ppt.

 

[Bumgrundle]

Sorry I always forget to convert before posting. 49.7 mS - 32.6 ppt - 1.024 SG
Breathing a sigh of relief! Thanx mate.
I often wonder why I do the Reef gig as i've never been the worrisome type....but i'm a mess when it comes to these creatures in my care.

 

[melypr1985]

I agree. Nem sting is very possible here.