I'm fairly sure this dragonfly was still alive (but too far for me to assist it out of the water).

Who knows how such a fantastic flyer ended up upside down in the water. Perhaps it narrowly avoided getting eaten only to be knocked in the water. Now all the creature can do is wait for Nature's fate.

Unless the dragonfly was especially lucky I imagine that it was a meal for either a bird or a fish. Such is the ways of Nature. It is an eat or be eaten world out there. Cycles must complete themselves even if it doesn't seem fair in our eyes.