Medicating my Angelfish (P. Scalare)

Question
I have four Angels in my 55 gallon tank along with 4 black phantom tetras
and 4 gold tetras. Two of the Angels have gotten a large build up of slime on
their upper backs and near the anal fin. What can I do to treat this and will I
be able to treat the two angels along with the other fish? Will they be harmed?
How long do they have before they croak? Any suggestions are greatly
appreciated...

From,
Will

Answer
There are a few things I need to know before I can adequately answer your question.  How often do you do water changes and how much do you change out each time?  Do you only have the 4 angels and 8 tetras?  If you have other fish as well, it could be from overstocking.  What I would do right now is do a 50% water change and do this twice a week or more.  If you feel the need to medicate you could try some melafix.