This is a great shot!! It looks like he is having a real conversation--emotionally--with the viewer/photographer. His eyes are simply wonderful, they convey such a sadness. Makes you want to break the little guy free.
In terms of composition, this piece works really well. I think you could play with some filters in Photoshop or another photo-editing program and get the colors to be a bit more saturated. That way he would really stand out! (Look at that fur, it's just begging to be shown at its full beauty!).