Last summer, I found this turtle in the middle of a road, 500–1000 meters away from a lake; it was dry and helpless. I decided to take it home and place it in some water, intending to consult a veterinarian in case its health deteriorated. I went to the nearest pet store, where a man told me it was a "yellow-bellied turtle" and that it would be illegal to release it back into the nearby lake, so I decided to keep it. At the store, I bought a plastic aquarium, a UVB lamp (as recommended by the man), and some freeze-dried heart-based food. Until a week ago, it was doing very well—eating and basking under the lamp whenever I turned it on (the man at the store had advised using it for 4–5 hours a day, positioned 10–15 cm away from the turtle). However, it has stopped eating and no longer basks under the lamp; it almost always stays hidden beneath the platform shown in the picture. Realizing that it wasn't thriving, I did some further research online. Based on what I learned from various sources, I realized I need to upgrade its aquarium, provide more water so it can swim properly, and get a heater to keep the water and the tank at a temperature of 24–26°C during the winter—to prevent it from entering hibernation or something similar. I am now asking for your help with some useful information—specifically, what kind of heating device would you recommend, given that the water depth is only about 10 cm? Also, should there be more or less water? I have attached photos of the old habitat and the type of bulb I currently use, as well as pictures of the turtle and the new, larger glass aquarium.