Ouch! White Cheek Tang has an accident!

[naesco]

It appears that your powder brown tang has been attacked by the scapel of another tang.\
Immediately remove the fish and place it in a QT. IMO that size of injury will not heal in the main tank as fungal and bacterial disease will doom your beautiful fish. Move quickly as a weakened tang will be victemized by the others.

Feed it garlic extreme soaked food. Garlic has antifungal properties.

Medicate carefully as per directions with Saltwater Maroxy by Mardel Laboratories. It is for true fungus and an anti-bacterial agent
Medicate carefully with a neomycin based anti-bacterial medication. IME the rest are useless product.