Cotton mouth is not one of the most common afflictions of goldfish, but is one of the more serious ones and one that often gets wrongly diagnosed. It can lead to a wide variety of health problems in the goldfish, and should be dealt with as soon as it is spotted, as it is very contagious and can soon go on to affect all of the goldfish within your tank.
If you want to ensure that you will be able to diagnose and treat cotton mouth if your spot it, read on to learn more.