Fix what? I like it as is. To me the dark top balances out the light in the lower half and I find that aesthetically pleasing.
The tones are good and fit well with the image, I think more colors would only much it up.
About the only thing I would tweak (and it's extremely minor) is maybe a slight crop in on the sides to get rid of the palm frond on the upper left edge and the shadow line on the right edge.
