Hmmm, wanted to like your post as I agree but the like button seems to be missing for me at this moment. I'm also going to move this to an appropriate forum section as this area is for Awards and Nominations.That is not a Dorado but it is a relative,it is a Brycon but I am not sure of the exact species.
It could be a Dorado, I personally don't have enough knowledge of them to rule it out. I just figured Brycon are more commonly available so more likely. Perhaps presumptuous on my part and for that I apologize.Not my area of expertise but could be B. rubricauda.
Also interested as to why folks rule out dorada (B. mooreii ) so easily/ quickly?
How big is the fish?