It's just that too many turtles have been stimulated by hormones since childhood, so the color of ear spots is dim and dry, and the color of turtle shells is not so bright. A turtle with a particularly bright color can only say that it has less hormones, but it is not sure that it must be healthy. Just like when we look at babies, we always think that fat boys are healthier, but it's not entirely right.
A turtle that my family bought before has been kept for five years. At first, its color was very dim, and even being put together with other turtles would be disliked. But later, with the improvement of dietary conditions, its color has been greatly improved. Now the color is better than that sold in most aquariums. Of course, it is much worse than a turtle that breeds by itself and hardly touches hormones. After all, it is congenital deficiency and acquired deformity.