So I bought kanaplex from a LFS I didn’t know was around here; found 2 more fish from the main tank showing symptoms and I’ve decided to break open the piggie bank and go scorched earth on this. Treating the entire 125g planted tank with Furan 2 and Kanaplex. There are so many driftwood hides and plants, as well as so many small fish, that trying to check and quarantine each one would involve destroying a scape that’s taken a year to get fully established and grown out. I have heard Furan 2 is rough on plants, but I’d rather have some die off from that than spend an entire day or two emptying the entire tank and tearing it apart; or missing 1 dwarf Cory hidden under a crypt leaf that restarts the whole process.
I have cycled media in other tanks to help restart the filter after I’m done with the meds, as well as a large bottle of Searched stability and prime. Also going to throw some hornwort from my Tang tank in there to help keep up with the restarting cycle... on a side note, I can now be a living example of why you need to quarantine extensively NO MATTER THE SOURCE, friend, store, etc.
Quarantine is not a 100% solution to virus or bacteria disease. It can avoid introducing large, visible pests like fish louse or leech, though.
It can happen that two groups of fish live healthily on their own for months but become ill when they are mixed.