Those are defiantly Bolivians

They will change color depending on mood. Both males and females. When they are stressed or sleeping, they will turn almost black. Don't be freaked when you turn on the lights in the morning and they look black. Its normal. Also, the intensity of the color comes and goes with mood too. They remind me of the old mood rings sometimes LOL
Fatten them babies up! It will be hard to tell male from female until they hit almost 3" and the males develop the long fins on them, How big are they?