I have a new idea that maybe his tank is still too cool. The air itself isn't warm when I put my hand in the tank, resulting in only floor heat that is just escaping. I do have a foam board on top, but it doesn't seem to be doing enough. I ordered a small dimmable clamp lamp and ceramic heat emitter that will arrive this thursday. Hopefully, by making the air warmer, it will encourage him to be a little more active and thus more interested in food.