hey guys so i have attached 2 images at the bottom of this post in hopes to get some input from you guys. my turtles shell has gotten a good amount of discoloring on the back edge of his shell mostly. Its almost like a metallic gold, which is a lot easier to see when he's in the water. He acts perfectly normally, and his shell is hard but i figured this much discoloration warranted a little bit of worriedness. Please guys let me know what this could be.

