Unfortunately like many other pathogens, if it is on one fish, it is already in the tank. Uronema is not an obligatory parasite, it is opportunistic parasite, so it is very hard to get rid of it. Even if you remove all the fish and treat them, (unlike ich or other obligatory parasites) uronema can still survive just like a regular, non-parasitic protozoa. That is why you need to nuke the tank to get rid of it.
It not as contagious as ich, brooks or velvet, meaning it will most likely not target healthy fish. You can live with it as it will not wipe a tank with healthy fish. But the fish is weak ,and particularly, if it has open wounds, it might get uronema. Fish that fight are prone to it (such as anthias and chromis), becouse they wound eachother and get infected with uronema afterwards.
If it is uronema (just google and check the pictures to make sure ), formaline or qp is a better choice compared to copper to treat fish. But the bigger issue is to deal with the uronema within the tank.
