Doesnt like to eat.

I have an 11 month old red nose pit. within the past 2 days he hasnt been eating right... His bowl will stay full all night with food. Today i did a little test though... i take about 10 pieces of his food and put it on the floor next to his bowl, and he comes over and eats it off the floor. From there he will then go to his bowl and eat like half the bowl the stop and not touch it again. I repeated what i did and he did the same thing, but finished the bowl. Anyone have any ideas why he would be doing this?

Here is the little bugger!!