Hi. I'm new to the turtle world. My boyfriends dad found a tiny red eared slider at his back door. It had walked a long ways from where it was hatched and was confused on how to get to the bayou. I didn't want to just throw him back into the wild so I brought him home and put him into a plush 20 gallon tank with all the amenities he could want. He was doing great for a couple of weeks and yesterday he started spending the majority of his time completely submerged under water. I'm nervous that he may be sick. I have done a lot of research and some people say this is normal but I am very worried. Please help!