Koi with Ulcer

[Fishnut]

One of the new koi has the beginnings of an ulcer on it's mouth .  It's just really red in one corner, so there's no gaping hole or giant bloody patch.  Thankfully not the expensive one, but a nice koi none the less.  I've separated the fish and treated it with salt (3tbsp per 5 gallons).  The rest of the fish in the pond were caught in a plastic bag for a close inspection and thankfully are all clear!  My water has been great in the pond so I can only assume that there is or has been some kind of parasite that affected this koi and has now left an open would for bacteria to get in.  Just in case, I also treated the pond with the same concentration of salt.

What I'm wondering is if anyone has had any luck treating the beginnings of an ulcer with just salt?  The books give examples of koi with really bad ulcers where the steps are to anesthetize the koi, scrape off the dead skin and scales, put some ointment on the ulcer and then spray it with this water proof stuff that seals in the ulcer with the medicated ointment.  Frankly, I don't want to get into all that if I don't have to.

Any words of wisdom?