That's a pretty fuzzy picture, but my guess is that it's a painted turtle, specifically (or that should be subspecifically), a Midland Painted Turtle, Chrysemys picta marginata. In the United States, we commonly refer to all Chelonia as "turtles". In other parts of the English-speaking world, turtles are found in the sea, terrapins are found in fresh water and tortoises are found on land. What you have there is a terrapin, or freshwater "turtle". He (or she) will live quite nicely in your pond but, unless you have some sort of surround to keep it in, will likely eventually wander off. By the way, if you can get close enough to see its front claws, the male is identified by its especially long claws, while the female short claws. Other methods of establishing sex are too up close and personal to be of value to you.
It might be another species, but it generally looks like a painted turtle, especially with those prominent yellow stripes on the head and neck. If it is, indeed, a midland painted, the stripes on the legs are usually a slight orange-red in color. Yellow-bellied Slider's range does not include Kentucky and the yellow near the eye is stripe-like rather than the large blotch found behind the eye of the slider.
My pond was built to house the turtles I had in classroom for many years. I have Western Painted, Midland Painted and Red-eared Sliders residential in my pond here in northern Illinois.
Don Perry
