I think I see it clearing up actually so I may let it sit a while
longer. What looks like is happening is that the whole "bubble" is has
a shorter diameter but still sticks out just as much, so the dotted
part around the black part of the eye is now visible. In other words,
it *may* be slowly clearing/draining. I can definitely see more of the
eye underneath now, so my guess is that I should keep things as they
are. It Also seems more likely that this is the original eye cover,
just thicker and yellower.

never ever use Pranzi, it is toxic to fish.

Praziquantel? It is? Everything I see online says things like this:

"Because it's gentle, Praziquantel is, and always has been, the
"treatment of choice" for Flukes (trematodes) in fish. Praziquantel
does not require water changes, praziquantel is harmless to fish of
*all* species including Discus, Koi and goldfish fry, and is non toxic
to plants, and; (unlike Formalin), praziquantel has no negative filter
impact."

http://www.fishdoc.net/articles/deta...p?articleId=25

Are you saying it's toxic in the recommended dosages? Do you have data
that contradicts the vast majority of information out there? (I'm not
saying you don't, I'm just trying to get better informed about all
this.)

lower your salt to 0.1% and I think the thick slime coat may disappear and the thick
covering over the eye too.

This fish doesn't have a thick slime coat, though. Just this eye
anomaly. The slime coat seems quite normal.

... high salt will trash the fins.

I've heard different thoughts about this lately, but I'm surprised
that .3% is considered high by some people and completely acceptable
by others. There must be some data to back up one camp or the other.
I'm surprised it's so recommended if there's a problem with it. A
search on "koi .3% salt" shows lots of support. I've even seen
recommendations of in-pond .5% to kill parasites. I was actually
planning on backing the salt off to .2% starting today to start
bringing it back in line with pond conditions, but until recently I
hadn't heard anyone saying that .3% was considered excessively high,
and the fish seem to flourish in it.

Also, the fins look fine. I'm pretty sure that the one with the tear
snagged on the net or something during the trip to the Tricide-Neo
dip. No other fins on that fish are torn, and the other two
hospitalized fish with damaged fins are actually healing now. I
noticed lots of new tail fin growth last night. They're all at .3%.

Dave