The largest fish has a pimple left over at the center of the original
infection. From what I have read this is Columnaris. Any thoughts on how to
treat this? So far they've had Kanamycin for the Columnaris and a long
treatment of Marycyn II for the Septicemia that followed. The Kanamycin
helped with the Columnaris, but did not wipe it out completely. Another
round of Kanamycin or perhaps Furnase?

I'm going to give them a break for a day or so to see how they make out, as
I can always nuke them with PP (lifetime supply).

BTW, I finally realized how they got this. I raised the temp a few degrees
when I added the infamous plant + I has having the filter flow issues. BINGO
Flexibacter took off. :-(