You'll have to permanently quarentine the remaining fish. They are to be considered carriers now. Even if they never show any symptoms. The good news is that some fish can be exposed and never develop the characteristic boils erupting from the skin. It's just a big lottery.
Sporozoans are the most resiliant of all the fish maladies. There is NO cure other than destroying the stock and thoroughly disinfecting EVERYTHING. Potassium permanganate cant touch it at 4ppm, malachite green/formalin cannot touch it. Bleach CAN touch it but only in concentrations much higher than any fish can withstand.
ANY fish that has ben in the same water column as a fish infected with sporozoans is a possible carrier. ESPECIALLY in pet shops with a shared filtration system. In fact, pet shops are the number one source of all infectious agents that affect our fish.
So, I guess your just going to have to keep a close eye on them. If you ever see ANY boils beginning to emerge from any of your remaining fish, remove it to a hospital tank immediately. The idea is that you do not want the mass from inside of the boil to treach any of the fish in the tank......
good luck and keep us posted!