NEED HELP FAST! Please!!!

[Candi1990]

I have lost 3 fish, about to be 4. And more to come. I lost them one at a time. I thought they were looking alittle black and fuzzy. Especially in the mornings. Today i noticed a white fuzzy stuff (fungus maybe) on the fins of one that is dying now. I have about 4 left now and want to save them please help!

 

[venymae]

try googling "fin rot" it might be what they have.