neons with white growth on mouths

[Fishi123]

hi i have 6 neons in a 10 gallon tank with 1 betta 1 mollie 2 guppies and 3 coryadourus.All of the neons have a white growth on their mouths.I have tried anti fungus and tested the water and all is fine what should i do.

Any help would be great thanks

 

[fishlover22346]

well I can definitely tell you that the tank is waaaaaaaaaaaaaaay to overstocked. all of these fish would need around 30 gallons. sounds like fungus, but the fungal treating won’t work unless you have wet clean water. what type of testing are you using? it could be wrong, depending on the type.