Although the winter days aren't that cold at the moment it's nice to see a nice tropical image. Nevertheless here are some crits if it's OK for you:
I think the water is way too rough. Looks a bit out of scale. And somehow the colors look cold to me. The shallow water could be a bit more on the greenish side and if you'd make the sand a tad more yellowish and the water's decay distance even deeper, it might look more tropical. Just some thoughts. I hope you don't mind.
