This is clearly the luckiest duckling that has ever lived. Swallowed by a fish then rejected to swim back out to the surface. I think it was probably bad timing on the baby ducks behalf.
Makes me wonder how many ducks and other aquatic birds get preyed on by fish. There is a reason very few ducks swim along the Murray river, those big cod are just waiting to gobble them up. Would happen in all waterways I could imagine.