It very wel could be forbis...I just thought i would bring it up just in case there are other ideas or possibilities...but yes could be a bruise from the barbs of my urchinI see something that kind of looks like a bruise. Could it have had a run in with one of your urchins.
You know it's a metallic fox rt? LolHonestly just looks stressed right now.
Naso tangs will tend to lose their color like that and have dark blotchy patches or spots.
I say give it a few days and see if it goes away and it regains it's color.
Yes but it looks like discoloration near the tail in the first picture. Perhaps it's the pattern. Hard to tell.You know it's a metallic fox rt? Lol