What caused this?

[reeferman1]

My YWG was fine yesterday morning and when I got home from work the back fin and the attaching muscle looks like it was peeled back on both sides. I have 2 clowns and a LMB which are fine. I just got the YWG on Friday. I've heard that the LMB could be aggressive with other look a like species, or maybe the YWG got his fine caught in the intake of a Maxi-Jet. Please advise. :notsure:

 

[lion_crazz]

I highly doubt it is the lmb being aggressive. They do not look similiar enough for the lmb to be territorial towards it.
Do you have any large hermit crabs or other types of crabs/lobsters in the tank?

 

[reeferman1]

Lion-crazz, I have a few small scarlets and 2 cleaner shrimp. Could a coral have caused this?

 

[dougai]

is it hanging of the back like he molted or is it like discoloring?

 

[gafish]

I have a lawnmower blenny that is aggresive so be carefull.

 

[reeferman1]

It's almost like the first layer of skin has been peeled off.