Hello,

I use under the tank heat instead of a light. 78 degrees is still low. Normal 85+ day, night 70+. 65 at night is cold.

He looks fine and fat. If he is not eating, he could just be adjusting and additional heat would help. Try other food items once the temps are up.

They will spend most of their time dug in, so it you want to see him, keep the soil only as deep as he is tall.

Cheers