Looking for Basics

Okay, so I am an avid snake owner, two boas and a cornsnake for about two years now.

Anywho, Snakes are easy to me.

Well, last year around July, I went to the KC Reptile Expo and bought a very small, aquatic turtle for my son.
He thought it was the greatest thing ever, named him ocean, and has been very adamant in taking care of him (hes always asking about food, when he can clean it, and when hes handling it, he is very gentle and extremely protective).

Anywho, as a child is technically taking care of the turtle, im the adult here and MUST learn more about aquatic turtles.

Now they look like yellow bellied sliders, but the man who sold Ocean to us said he was just a regular aquatic turtle.

Is there anything I need to know besides, warm-ish water, good land access and a hide for this little dude?
Hes currently feeding on a combination of aquatic turtle pellets (which dissolve and get gross in the water (are they supposed to do that?)), and meal worms every now and again.

Any tips, tricks and/or suggestions on how to improve this little guys life would be most appreciated.
Thank you!

Jaymie