Hello! I am the new owner of a Murray River Turtle called Yertle. He is very fun and loved and man does he have an appetite. I have gone out of my way to care for him (and pamper him) so I have a nice setup for him. He is only a baby and I adopted him 3 months ago. He eats well, digs, basks and follows people around the tank. He is very friendly and constantly comes up to say hello. As this is the first turtle I have ever owned, I get a little worried that he is sick. (Probably just an overcautious mother) Anyway I have attached a photo of him he seems pretty happy, but I noticed his shell has started to darken and was wondering if that's normal?