All of a sudden, my dog (6 yo Tibetan Terrier) won't eat from his bowl when it's sitting on the floor. I put it under some books and he's fine. Also he's happily drinking from his water bowl, on the floor 
Other than that, all is normal - happy, energetic, not off his food, pooing fine etc.
Is he just being a fuss-pot or is there anything I should be worried about?