I think the concrete answer is male. Three of us agree on that.
The shape of the body and the it's color. Females mare more yellow and more shaped like torpedoes. This guy looks beefy and he looks more goldish than yellow.
beside body shape and fin the male Jag will lose the black marking and replace with black dots pattern, look at your Jag picture the black marking starting to fade out (the female Jag most of the time will keep the black marking for the rest of their life, there is some cases The male jag still keep the black marking but still look different compare to female jag.) Your Jag def. a male one.as i may want to breed, what are the characteristics that show this is a male?. thanks