Phantom fish deaths

Cotton mouth, I have just inspected my tank like there is no tomorow, one of my guppies has cotton mouth, this is possibly whats killed my other fish as they all slime over when they die so this is a symptom i would have easily missed after death, this been an aggressive (parasite?) would have caused the fast deaths. so for the next week i will be using melafix and cranking up my water changes. If anyone has a better treatment for this I would really like to know as I do not want to loose any more :(

Looks like the ornomant may not have been the cause
 
thanks for this info, If my little fish takes a turn for the worse I will give this a try, but right now she seems a little better, she has gotten some of her fin colour back so thats a good sign.

I am doing water changes and gravel clean every day, after doing this I add salt and melafix and just for the sake I am adding white spot which I have used in the past for parasites and works quite well. So far though, touch wood, she has colour back in his fin, an hopefully I can get her eating soon.
 
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