Depends on their size.....they won't really start pairin up till they are at least 7 to 8" long. Before that, they will just hang out together for the most part for 'companionship'. Lugubris pikes are one of the few pike groups that will actually 'school' together while they are still juv. with little aggression. Its once they hit subadult that the problems start. Unfortunately, Saxatilis pikes don't have this same behavior and dislike other pikes right from the start.