I have a 5 inch freshwater atlantic ray. Shes in a 100 gallon tank, no other fish, thermo set to 77 and "the measured amount" of aquarium salt (intended for tropical fish) Shes eating great, but today she is swimming in circles and her right side is noticably curling! no discoloration on her disk. Any suggestions??? I tried taking a picture, but shes moving too much and the photos look normal.