Hello Dan, watching mine, the agressive traits are about the same as fresh water perch we used to catch when we were kids fishing. As long as they have places to hide, I would think they would be ok. You can make fish caves from a coconut or two. Split them in half, clean out and boil until you get most of the tannins out and cut out the "doors" with a pair of wire cutters or something suitable (that's what I did).