Most aggressive fish I've owned was my Jardini before I sold him. Now, my Channa Micropeltes is the most aggressive. He bit 2 silver arowana's that were 2" shorter than he was at 15". Now he's in a community tank @ 16" w/ a silver 3" longer as well as a 14" Florida Gar, a 22" Channa Maruloides, 8" Red Oscar and a 10" Marbled Motoro.....weird.