no one has any idea whats wrong with my fish

Question

molly   my molly fish about a month ago gave birth and since then the males have been removed from the take as i want no more babys she started to become ill (she could have started to become ill while the males were still there, i cant remember) but what has happened is her left fin in orange a rusty brown orange and it flakes off and has blisters filled with fluid
she still eats and swims around happily but her fin is getting worse.. ill attach a picture  
her other fin is fine

please please help,

Answer
Alannah,   This is called hemorrhagic septicemia. It is a bacterial infection. You need to go to the pet shop and get Erythromycin or Maracyn-2. Treat as it says on the package. It is probably 1 packet per ten gallons. Do not forget to take your carbon out of your filter so you do not filter out the medication. After you are done the treatment and I would do 7 days do a 40% water change and new filter cartridge and you should be fine. Mollies' are very strong fish though she may carry some of the scars from it ....like some permanent discoloration. Keep an eye on it always just because she is going have delicate spots. Good Luck, Tina