I have a concerning issue that I need some help with. One of my RESs will not move very much. It will sit on the rock under the basking light and will not move. It just sits there with its eyes closed and its limbs tucked in. It is still breathing, I have been checking every few hours. The little guy will not get off the rock. When I feed the rest of them that are in the tank they will eat, but this one I have to put in the water and most of the time it will not do anything, but float then it will swim back to the rock and stay there.The RES is in a tank with a few other ones that are the same size. The other ones act like normal, swimming around, eating, basking, begging, and jumping off the rock when I get close. I don't know what is wrong with this little guy. I am concerned because I am out of town right now and won't be home for another week. Any help would be appreciated and sorry for the long sermon.