I started off with a 10 gal. and 2 Jack Dempsey, 2 Venustus, 2 black neon tetra and a pleco ( yes all in a 10 gal tank)
needless to say, not knowing anything about the tiny fish that were oh so cute when I put them in, I was left with 1 Jack. He killed all my other fish. Well, all but the tetra's.
in my 60 I have a Jack(my original), Venustus, Fuelleborni, Yellow Peacock, Acei, Living Stoney, Ice Blue Zebra, and a pleco. no fights so far, which I'm told is "not normal" my Jack should be killing everything else apparently