They get more iridescent when growing older. Mine were then Xenotoca variata, Jesus Maria.
Love the pic you've showed. Now you see just one come out at that moment. But sometimes two or even three come out at the same time.
male Jesus Maria. they're really nice looking fish I have seen many goodeids give birth
there's almost always the odd one or two come out head first I have also seen them give birth to more than one fry at a time ,