From what I've gathered my koi's problem may be:

Carp pox (aka Lymphocystis)
Or
Koi herpes


I'm unclear on whether or not Carp Pox and Koi Herpes are different
diseases or just the same name for the same thing.

I don't want to kill the fish, but it certainly sounds like I should
isolate this one. That's a bit of a pain considering the size these
fish are getting to, but one thing I learned is that these bigger fish
are much lazier and easier to catch than the impossible-to-catch
younger ones. I definitely don't want to contact the Department of
Agriculture. Government and environmental issues are a scary thing to
mix and I've heard the horror stories. I'd probably end up with 100
euthanized koi and a demolished pond. I'll be lucky if they don't
find a way to condemn my property altogether!


I would like to get out of this without the death of this fish. I've
never really liked its color patterns too much but that's a mean
reason to settle for its euthanization!

Don't worry; the last thing I'll do is release this fish into the wild
or any other body of water for that matter.