I am currently raising a batch of GT and segregating male and female as soon as they pair up at about 2 inches. The first pic suggests it is a female because of the dark color and the characteristic double vertical stripes. The second pic looks more like a male because of the lighter and brighter color, but could also be a dominant female. In my segegraged female GT tank, the dorminant female assumes a male color and could easily be mistaken as a male if not because I spot her paired up with a male. Another way to tell is the vent area. A male will have a horizontal flat belly. A female will have a bulging belly protuding at the vent pipe.