My platy has white spots on her tail

Question
My platy fish was not eating for a couple days.  Usually this means that the fish is sick.
I separated her from the rest of the fish and put her in a 5 gallon tank.
I did not know exactly what it was, so went ahead and gave her Maracyn 2, then added Maracide after 4 days.  She is still not eating and has developed white spots on her tail (almost look like little white bubbles).
I removed the carbon filter while she was on Maracyn 2 then put it back in when I started the Maracide; and kept the heat around 26 celsius.  I tried to keep off the light more as recommended for treatment.
She has now been in treatment for 5 days, and sick for 9 days.
What do I do?

Answer
Alex,

  The rule of fin is never treat a fish with any medication unless you know for sure what is wrong. Doing this can make the fish sicker. It is hard for me to come to a conclusion without a picture.  It could be cotton wool disease, mouth or body fungus OR true fungus. If you can, will you add a picuter so that I can see the fish. I do not want to start treatments that might not work for the wrong disease. Also, just because a fish does not eat does not mean it is sick. Sometimes they are just not interested the first time you feed them.