I have a 5 gallon tank that has 2 adult female platys and a number of fry from both. I had a male in the tank but he passed a while back, shortly before the fry were born. Now i have a semi fat female, i assume she isn't pregnant, and a really skinny female. I worry about my skinny female, it...

I have a 2 year old female Micky Mouse platy named Mini. I've noticed about 3 weeks ago that she has a blue-greenish spot on her head that has never been there before. For the past two weeks her fins have been clamped down and she's been hiding. I've put some salt in there to relieve stress but...