Hi Jim,
Thanks to John Neville we can see your unusual picture. There is so much to this. From the plain survival standpoint this is an amazing glimpse of the birds imperative to burrow into the water to get it's food. If the bird was a millesecond off, the fish would be able to spawn another day perhaps. Not getting the head, is part of the picture of what is happening.
Besides the birds need to eat and your need to record this beautifully catch the Grebe Dive with it's head visible I think that this photograph is impressive just in its power and shapes. The contrast of opposite surfaces: solid versus liquid versus air; rough textured feathers versus smooth water.
Thanks so much for bringing this picture here! We do love bird pics as well, even the whole bird, but this is something special.
Asher