Black crud on fish lip? HELP

[username]

I had a really pregnant fish. She had all of the signs of being pregnant. One day I noticed that she had a little bit of white stuff on her lip. Immediately I put ick medicine in the tank. The next day it was gone. A few days later the ick was back but this time some weird black stuff was hanging off her lip. She died but I am curious about what it is. Any ideas? She only had one baby before she died. Here he is.