Possible hole-in-the-head (HITH)?

[Michael Almeida]

This has literally developed within the last 12 hrs.
No new fish in the tank in the last 6 months.

He's a bit of a jerk in the tank. and is constantly harassing my Purple tang.

Wonder if he ran into something?

Thoughts greatly appreciated.

Temperature - 77-78F degrees
pH – 8.0-8.1
Specific Gravity – ~1.025
Alkalinity – 8-9 dKH
Ammonia – 0
Nitrite – 0
Nitrate – 50-60PPM
Calcium – 400-420 PPM
Magnesium – 1200-1250 PPM

 

[LAReefer4Life]

Looks like a sting? you have any nems or stinging coral?

 

[Michael Almeida]

Never considered that due to the perfect symmetry of the mark. That being said, I do have a rose BTA in the tank. And as of this AM the injury does appear much better.

 

[Michael Almeida]

A week later and the mark is completely gone. Just a little raised tissue barely noticeable is left.