There are usually 3 reasons why a new turtle isn't basking. One could be that the temperature isn't high enough. It should be 10 degrees warmer than the water, which should be around 78 (water) for a hatchling. Another could be, that he can't easily access the basking dock. The usual reason is that they are shy and it takes time for them to adjust to their new environment. Is his tank in an area with a lot of traffic? If so, you may want to put something up around the basking area to give him some privacy until he gets used to his new home.
Hopefully this helps..
What is your setup like? Oh and Welcome to the world of RES
