I have noticed that when Carpintis get territorial, or aggravated, many tend to show a large black area that appears on their upper back and on their dorsal fin. My last three males all did this. To a point where I second guessed if they were males. Until I vented them and they all were in fact males. I also have found that head profile varies based on collection point. Some males have very steep head profiles , while other males will have elongated faces that resemble a females profile, but grow a hump. With your new little ones time will tell.