Samandnelly, when you first pull up this website, redearslider.com, there's a little turtle with spots on his shell. Do those look like your turtle's spots?
My RES has black "spots" on his shell as well (much like yours). They're part of the pattern on his carapace, and look really nice with all the yellow he has on him.
"You become responsible, forever, for what you have tamed." -Antoine de Saint Exupery-