Very nice action shot. I looks like they are having a lot of fun. The lake and the hills make a nice background. Although it appears to be an overcast day, the picture as a whole is a little on the dark side. Perhaps just a little adjustment in post-processing would brighten it up a little. As far as the challenge goes, I define fauna as being more than the domesticated family pet.
could be framed better. the background doesn't add anything here. i think it would look better if the top and left side were cropped so the dogs were centered in the picture.