Fish continue to die over 6 month period

[Humblefish]

Thanks! So you would advise to do this vs take out catchable inverts, out in QT and return to DT after Formalin because of probability of Uronema staying inside invert shell and just transferring right back, correct? I also don't want to kill the inverts if possible.

Honestly, I don’t see formalin dosing working here (even with the inverts out) because of this: Biodegradation - Are bacteria rendering your quarantine process useless?

I feel metro dosing would be a better option to try because it tends to linger longer in the water in an established DT (meaning, bacteria seems to consume formalin faster): Metronidazole

Metro is also quasi-invert safe provided you use DMSO to fully dissolve it before dosing: How To - Use DMSO to dissolve medications

To be clear, you have no good options here… nothing is guaranteed to work. Except for bleaching the tank and starting over: How To - Sterilize + reseed any tank

 

[Humblefish]

I personally would give the 6 week peroxide regimen a go, and then get an eDNA test done afterwards: Introducing the tankDNA Test