Glad we're on the same page! Just to give you an idea of how aggressive they can become (as you have not seen their worst side yet).
In an earlier time, when I had no clue about fish keeping, I purchased 3 Black Convicts hoping they'd pair off. They did in about 3 seconds and within 2 hours COMPLETELY DE-SCALED the other Convict. It was black when I put it in there, when I took it out it was pink. I placed it in a community tank and tried to nurse it back to health with melafix unsuccessfully.
If I were you I'd bag them now and head straight to the LFS.