Black Stuff On Fish

[MisterGQ79]

I have black stuff on the top of my orange platys and I believe it started with the bleeding heart tetras....one of them started to look "dirty". Anyone else have black stuff on the top of their fish? Thanks.

 

[tttnjfttt]

This sounds like a parasite infection, known as "black spot". Is this why you are treating your tank with copper safe? Have you checked your water stats (ammonia, nitrIte, nitrAte, and pH)? Are the fish scratching on objects in the tank?