The object was not noticed at the moment of taking the photograph, but only when it was enlarged.

This photograph was taken from the seaside front in the city of Piriapolis in Uruguay, on the coast of the Rio de la Plata river. The coordinates are: -34.863468773203735, -55.27964588674423.
It was taken at midday, Uruguay time, on November 15, 2021, using the camera of an iPhone 12 cell phone.
The person who took the photograph did not notice anything strange, he just liked the great view of the water, the clear sky and a sailing boat. A few days later, he looked at it again and noticed something strange in the sky, something he had not seen at the moment of taking the photograph. He enlarged it using the Let’s Enhance app. It is not possible to confirm if it was moving or not, but by the image it seems to be still.
I am attaching four photographs, the original one and three stages of amplification.
Using the normal UFO classification names, I would say it is cigar shaped, but it actually looks like a fish. The front half looks like a shark of a whale, and the back half like a metallic object, an airplane with no tail.
I completely trust the photographer, and I know it is not a hoax.