The turtle blends into the background making it difficult to look at. Also there is a center composition that really does not work here and the turtles head is facing away from us. I see where you were going with this and it is a neat idea but you couldn't quite get it in this shot. Keep trying.
And in case you were curious, it is a Pseudemys rubriventris.
Nice concept but it really needed a much tighter crop as the majority of the photograph is just water. Between the tree limb and the turtle, you have more then enough interesting subject matter, to fill the majority of the frame.
It's all the same color, there is virtually no contrast, too much compression, too soft, no details of the turtle can actually be made out, overexposed, most everything above and to the right of the turtle should be cropped out.