Sohal Tang Scalpel Injury help

[asylumdown]

Hello!

So I had intended my first post on this site to be a general introduction and hello, but I'm afraid that will have to wait as something urgent came up today.

I have a medium sized Sohal tang that has been in my 90 gallon display for 2 weeks now. He's acclimated nicely and now eats pretty much right out of my hand. He was purchased knowing that he will have a 230 gallon home to move to (under construction) as he grows and he is the only tang in the tank.

I came home from work this afternoon to discover that his left defensive scalpel is 'stuck' in an extended position.

His only other tank mates are a pair of cinnamon clowns, a female lineatus wrasse, a cleaner wrasse (which eats voraciously, though he was definitely an un-researched impulse purchase) and a neon dottyback.

water parameters are:
ammonia 0
nitrites 0
nitrates - under 5 ppm
SG 1.025
25 degrees
calcium 550ppm
alkalinity 11.7
pH 8.2

If anyone has ever seen an injury like this, or knows what could have happened I would greatly appreciate the feedback. Better yet, if anyone knows how to treat this injury before he rips the scalpel clean off on a rock or injures another fish that would be sweet.

Thank you!