lol this would just confuse the cichlid peeps
Better posting in "Cyprinids, Characins and Atherinids"
How ever Black widow's are egg scatters, and if you dont see them spawning you not nottice the eggas as their quite small and the will fall between gravel and all fish love eggs so they will soon be eaten up if left alone.
If you want to breed these fish you need soft water, and they should have a tank of their own.
Rearing the fry are difficualt and not simple. you should look into growing some simple live foods like micro worm and baby brine shrimp.
Helter