In the last 24hours ive had 2 other fish die this is my third that has gotten this molting looking stuff on her. whatever it is it works fast and it somehow bent her back; the other two werent bent. but they all had some sort of like white molting on their bodies. my female betta had it on her lips. this one has it on her midsection. please; what is this and how can i stop it from spreading????