Opinions on injured fish please

[Ogre44]

Back in the beginning of November I bought some angels to go into my 65 gallon tank.
I put them through QT and about a month ago moved 3 of them into my 30 gallon as the 4th had some stringy feces issues I wanted to finish clearing up.
Last night I moved all 4 into the 65 gallon, which was a new territory for all of them.
I went to check on them after lunch and the 4th fish that had remained in the QT tank had a hole going all the way through him, just above his anal fin:


I know that angels can be territorial with new additions to their tank, that's why this fish never went into the 30 gallon and I introduced all 4 fish to the 65 gallon at the same time so it didn't belong to any of them.
Does this look like an injury inflicted by one of the other angels?
Other tankmates include Harlequin Raspbora, Keyhole Cichlids, and Bronze Corydoras Catfish, and I've never seen any aggression from any of those fish toward each other at all.
I would swear that before this morning this fish was fine, no bumps, no odd behavior, nothing.
Heck, the stringy poo issue cleared up when I quit with the Metronidazole I use for preventative for internal issues in QT.
I'm baffled and quite worried.

Ive got him back in the QT for now, not sure how to proceed other than very clean water and observation.
Suggestions and opinions would be very welcome.

[Somethingsfishy]

Sorry, but I have no idea what it is.  Hopefully someone with more knowledge will come along soon with some advice.  Just wanted to wish you good luck solving it.  I know how frustrating trying to figure out what's wrong with a sick fish can be!

[Regalblue]

Did you catch it with a skewer?   Do Corys have the hard dorsal/pectoral spine like other Cats?  Could it have gotten stuck by one? 

[Ogre44]

Corries do have very small spines, but I don't thing they're long enough to totally pierce a fish.
Perhaps he just wants to be punk?

[linuxrulesusa]

If you had a peacock eel, I have heard of them getting annoyed with a fish and drilling holes in them, but that usually kills the targeted fish. 

I'd watch it closely and probably put back in QT to avoid other fish getting whatever it has.

[Ogre44]

Yeah, he's back in the QT now.
So nobody thinks this is damage caused by the other angels?
This hole goes clear through him, I can literally see things through it when he's swimming around.
Whatever it is it came on in less than 24 hours.

[Somethingsfishy]

Could it be some kind of worm or parasite?

[rcombs]

the Indian in the cupboard when spearing in your tank