Ilham, I have no idea where they came from because I am the fourth owner. I think this pair has been around quite awhile, from what I understand, they spawned for the previous two owners as well.
As for their coloration, as long as I have owned them (about 5 months), they have been jet black.
I also confirmed that Rod will be raising the fry, as long as I can get him viable eggs. He's about a half hour from me so it shouldn't be a problem. Hopefully these lil' buggers won't miss a beat once I add a tile.