Post pictures if possible to help us understand the setup, it sounds like your hide is to big for the little guy. They like tight spaces, it makes them feel more secure. Just give the little guy some a week or two to settle in, if you try to feed him to early he will most likely just do defensive strikes at the food, but let him settle in and he will eat when he is ready. After 5 days or so of no handling offer him some food and if he doesn't eat it in a few minutes take it out. Typically if they don't eat it in the first 10 mins they won't in my experience, and it will only stress them out more.

15qt should be a good size for him, I recently put my 559g male back in a 15qt because he wasn't eating well in the 32qt, however my 647g male is very happy in the 32qt. Every snake is a little different.