Fin rot or battle wounds?

[FullBoreReefer]

Last night before lights out everything about my spotted mandarin looked normal. Woke up today and his back fin has some major damage. He has been acting fine and eating as normal but his tail fin looks painful if you ask me.

I'll keep updating with pics as he swims by.

Pretty much Im looking for advice or suggestions about weather or not I should remove him and treat him with a medication, please suggest that as well. Or just let him be and hope his tail recovers.

 

[FullBoreReefer]

 

[FullBoreReefer]

This was taken by my girlfriend just before lights out last night. Alittle hard to see but you can see the outline of the flesh on the fin. Looks ok to me...

 

[FullBoreReefer]

Tank mates...

Two false clowns
Three yellow tail damsels
Brittle star
Three emerald crabs
Six turbos
About a dozen blue legs
A few dozen nassarius snails

Tanks mates have been in there about 2.5yrs. The mandarin is a new addition. After time in quarantine and eating frozen foods, happy and healthy he was put into the display.