Spironucleus causes the muscle tissue to turn cream/ white and break down. The fish usually die within a week of this occurring.
Salt is about the only thing I have found to treat it.
Add 2 heaped tablespoons of rock salt, sea salt, or swimming pool salt for every 20 litres (5 gallons) of tank water. Keep salt in the tank for at least 2 weeks but no longer than 4 weeks.
If there is no improvement after 2 days with salt, increase the salt level to 4 heaped tablespoons of salt for every 20 litres.
Watch the fish when increasing the salt level to 4 heaped tablespoons and if the fish start to freak out, do a water change and stay with 2 heaped tablespoons per 20 litres.
When you do water changes while using salt, add salt to the new water before adding it to the tank.
