First of all I'm new at this but that's beside the point. Anyways I've noticed the past few months (maybe even longer) I noticed that on my two red eared sliders, there looks like there's gold on certain parts of their shells. They're about 12-14 years. I was also reading a book about red eared sliders that I have and diseases they can get and the only one that really popped out at me was soft shell but the pictures didn't look right. Any ideas?