I've quarantined a couple groups of anthias and have had uronema almost every time. I've been extremely successful using ruby reef rally pro and Metronidazole. I'll do a concentrated dip for 90 minutes and then treat the tank with Metronidazole. I don't like Formalin and Rally pro has been reliable. Formalin also expires within months of purchasing and it's usually expensive. Not sure if you've used Rally pro and Metronidazole as a cure but would recommend an experiment.