The reason I use black substrate, is I've heard it makes fish show their colors more. If you want your babies to have hiding places, just get a bunch of plants. I use both live and fake. I like the live because it's a snack for the fish, lowers toxins in the water, and oxygenates (not much, but better than without plants).
I use fake ones, because I prefer to keep my themes mostly blue and black, and live plants don't exactly come in those colors
The only bad thing about fakes, is they can cut the skin of fish if they swim against them wrong :/
Or you can get breeding mops... there's always some on Aquabid