My vieja has this pink skin tag looking things at the base of her fins. I have tried antibiotics and fungal treatments but no luck. Are they some kind of tumor? I have some picks and a small video of her.
If it is lymph, it is usually species (Genus?) specific, and can spread to other Vieja, but usually not other genera.
Stress will make it spread, anything from too high a temp, too high nitrates, or an alpha fish harassing the one with the virus can make it worse.
As said above, its a virus, so only a virus-cide is an effective in treatment.
You could try rubbing the infected areas with Acyclovir, but the stress of netting and being caught may be more of a negative than the efficacy of the treatment.
I had some Vieja present from the stress of shipping (it is ubiquitous, like the common cold in fish) and it went away quickly with daily water changes, and a stress free tank.