Can anyone identify these white spots on my gem tangs fin? (not ich)

[danosreefer]

woke up this morning to find my gem tang has 3 larger white spots on its fin. if anyone can help me identify these spots, that would be greatly appreciate!

 

[KrisReef]

I would ask the blue tang to explain the damage. Either stress or injuries?

 

[danosreefer]

I would ask the blue tang to explain the damage. Either stress or injuries?

i was thinking stress. funny thing is the blue tang is the calmest one out of them all lol