In article RFFxzJm83E64-pn2-o3NiFSz4z9Vm@localhost,
says...
Tested my water this evening.

ph = about 7.2
Ammonia = neutral
Nitrites = 0 ppm
Nitrates = as near as I can tell, about 80-100ppm (the instructions
that came with the kit say aronud 40ppm is normal. Thoughts?)

I don't know about the other fish in there, but goldfish
for sure don't like nitrates that high. You should do a
big (50%) PWC followed by another the next day.
Nitrates could well account for the symptoms you saw in the
Oranda. I try to keep mine at 20ppm or lower.

Also, I have originally added slat to the water, I believe it was
whatever was recommended on the container of salt that I bought
(1TBS/5 gallons water?)

The rules might be different for a community tank like yours.
For goldfish, 1T/5G is a pretty weak concentration, and is
usually what's recommended for a general tonic.
As parasite treatment, it takes about 10 times that or more.

Hmmm...I was about to recommend you check koivet.com, but they
seem to be down(?) or something.

No matter: salt won't help lesions much.
Do those water changes.