Cotton mouth


Also known as Columnaris Bacterial, Cotton Mouth is not very common, but does affect all types of freshwater fish. Typically looked at like a fungus, Columnaris is not a fungus. It is a bacterial infection and needs to be treated accordingly. Like a lot of other bacterial diseases, Calumnaris can be prevented by;

  • Quarantining new fish
  • Improving Water Quality
  • Reducing Organic Debris in the tank 


Symptoms can include;

  • cottony growth or white threads blowing out of mouth 
  • lethargic behavior
  • clamped fins
  • thick heavy slime coat
  • dry skin


Medicated food that includes Pottasium Permanganate is a good start for treatment. Otherwise an injection of antibacterial medication (if available), or Melafix will also work in the treatment of the infection. More importantly, very clean water is the best deterant to Columnaris, and many other bacterias as well.