Mould Patches On Neons - Wont Go Away

[MichaelCrook]

We have pimafix treatments but it just won't go away

and now it's fully taken over the back fin of one of our neons. Currently only 2 have it bad, here are their photos:

 

 
sorry the photos are bad, but it's hard to focus on them because their so small and there is net all around them to stop them from physically spreading the fungus to others from fighting.
 
No matter what we do we just can't seem to get it to stop growing. help, please.
 
edit:
Just doing a Tonic dip at the moment. We can't treat the whole tank as we have scaleless fish who would suffer if we put it in the tank. I have done 1.5x strength as we are only exposing them for 30 min so it needs to be a tougher dose. We are keeping a close eye and will repeat daily for 5 days. Any further advice still wanted.

 

[WILDER]

Sorry I can't make much out at all in the pictures.
Where is the fungus on the neons?
Does it look fluffy like cotton wool?
Any red, pink, or brown area in the affected area?
Is the fungus eating the skin away?
Any white fluffy cotton wool areas on the mouth?
 
 
Make sure that the neons red stripe area dosn't look bleached out.
 
How many gallons is the tank?
How many fish and which type?
Water stats in ammonia, nitrite, nitrate, and ph.