Jackedupjack

So I was fishing my pond and the bass are spawning right now. So I saw a bass on it's bed, but it was with a jet black fish, it looked like a crappie. The bass and the black fish would kind of rub up against each other and one would swim off and eventually come back, they were doing that all day. So I don't know what kind of fish the black one was and why it was there. I have a small pond, not even an acre. not a lot of bass in it, mostly crappie and bluegill. So thanks for any help, I just want to know what might have been going on there.