Black splotches on new Powder Blue Tang... what to do?

[pringlescan]

Today, I got a medium sized Powder Blue Tang from my LFS.

I noticed that it has some dark splotches towards the tail fin on one side.

Is this a cause for concern?

Full Resolution Photos for reference:
Dark Splotches on Powder Blue Tang - Album on Imgur


Background:

• 75 gallon with 20 gallon sump.
• 4 Months old.
• Cycled with cured life rock, live sand, bio-spira, stability and two medium clown fish.

Levels:

• Salinity: 1.025 (ATC Refractometer)
• Temperature: 80F
• PH: 8-8.2
• Nitrate: 0
• Nitrite: 0
• Ammonia: 0
• Phosphate: < 0.25 (It’s hard to read)

Last fish added:
Today, Tuesday at 2pm the pictured Powder Blue Tang was added.


Quarantine
It was not quarantined. I know this is a really good idea going forward. I don't have the resources currently and my girlfriend would really like fish in the tank


Acclimation:
I live 5 minutes from the LFS. To acclimate, the bag was submerged in the tank. Every 5 minutes, for 30 minutes (6 times), 8 oz of tank water were poured into the bag. The bag was emptied and the fish dropped into a bowl of tank water. It was then dumped (without using a net) into the tank.


Appearance

• There are dark splotches towards the tail fin on one side of the fish (at certain angles, they disappear, see photos).
• No visible white ich.
• No visible damage to fins or gills.

Apetite
Since introduction to tank, it has been picking at algae on the rocks and heater. It ate frozen food shortly after being added.


Behavior
The fish is actively swimming at all levels of the tank. It does not appear frantic and has proper buoyancy. It has a healthy appetite and did not show any signs of severe stress (shortness of breath), limited movement.


Thanks for reading!

 

[pringlescan]

The JPEG compression on the attached photos obscure the splotches.

Please see the photos as shot on imgur:
Dark Splotches on Powder Blue Tang - Album on Imgur

 

[miyags]

Hard to tell, looks like it got banged up a little while catching it.

 

[ChristopherKriens]

Minor injuries are visually exaggerated on Acanthurus tangs and other smooth skinned fishes. This isn't out the norm, especially on a "Powder" that's just been moved. Should heal up in a week or so.

 

[Humblefish]

I agree with both of the above; however if it spreads or starts looking worse, you may have to QT & treat with antibiotics.