It is around the size of a snapple cap and has a green top shell And a yellow bottom shell. It's skin is green with yellow markings as well As its face.
First of all, welcome to TFO. Secondly, I believe that is a yellow bellied slider. Someone with more knowledge than myself will be along shortly, I am sure.
Your picture is pretty blurry, but it IS some sort of water turtle. The care for water turtles is pretty much the same for all of them. They can't swallow food unless they are under the water. Babies eat mainly live food...worms, small crickets/bugs, etc. But they will occasionally eat some vegetation too.
Welcome to the Forum.
What would you like us to call you?
...and may we know appx. where in the world you are?
Does the yellow bottom have black markings? If yes then red Earred slider,
If it is a solid yellow, it is a yellow bellied slider,
A few more pics of the face and underside will help
my guess is, something other than a red ear, but the care for what you have would be the same as a red ear. a good pic of the bottom could help identify it.
It's a yellow bellied slider, even as hatchlings red eared sliders have bright red marks on there head/ears... so you have a yellow bellied slider.. it's the same care and set up as a red eared slider.. they make great pets and are so fricken cute