The pose is very nice and the fish adds to it. The light really was not with you here and it looks a bit flat on my monitor. I would put the bird higher in the frame and give it more room to fly into.
There are several things you can do to improve this image. The first thing I would do is to get the image a little brighter. The image looks very dull and flat.
I would also leave more space in front of the bird, as with your current composition the bird don't have space to fly into.
One final step would be to push the colors for the beak and some USM.