Stephanie,
I used to keep aquatic turtles, terrapins to be exact (malaclemys terrapin terrapin). They are turtles that live in brackish water, were once considered especally good eating, and were raised in farms along the gulf and carolina coasts for that purpose.
A place to crawl out of the water is essential, but rocks can scratch or otherwise cause damage to the plastron if they are too rough. Look for well-rounded pebbles, or fairly large flat flat surfaces. The best material IMO is cork bark. It floats, and can be secured to the side of the tank relatively easily. Then the turtle can climb out to bask without risk. I kept mine in a tank 3' sq. and one foot deep. They lasted for a good many years until a winter storm cut the power. I couldn't keep the temperature up and the developed pneumonia. UNfortunately nothing mucgh to do in that case.
Good luck: what is Sasuke, by the way? In my experience red-eared silders (pseudemys picta, I think) are the most common, perhaps followed by yellow-ears, often called "cooters." I think they make great pets if you're not expecting an outpouring of affection.
Lee