okay here we go again i have another illness. one of my female platy's (in the 20gal tank) started acting very strange lastnight. She was at the top corners breathing then acting lethargic. This morning she is sitting at the bottum resting there and super super skinny. I just placed her in my other tank along with the other platy and she is sticking to the top still. She also has a yellow colour to her now (she is all white usually) is this a parasite or disease please tell me so i can treate the issue and also for future outbreaks. ty.