The first photo is definitely a male of the natural colour. He has a black throat which only males have.
The images of the yellow, man-made variety aren't clear enough to be totally certain but I suspect a male as it does not have any trace of a broken darker line form nose to tail. Females of this colour variety usually, though not always, have this stripe. The third photo appears to show a darkening of the throat but this could be a shadow caused by tank decor. You can see the fish in the flesh - is there any trace of a slightly darker throat? And is the yellow colour the same shade all over the body or does it become orangey towards the tail?