Not a very clear picture. Where did you get them from? Perhaps your supplier can inform you on what they are. Or if you can get a clearer picture, we might be able to help you out. But of course, breed away : )
If they're pure black, you have a very rare and expensive shrimp there. What kind of shrimp do you have in the tank already? Sometimes the Malaysian ones (sometimes sold as Blueberry Shrimp) are a pretty dark blue color, but not black.