I have them in a 6ft tank with a river type situation, where flow starts on one end, and overflow drilled on the opposite side, maybe 1000gph.
The flow enters right above where they have placed the spawn, a sort of counter current zone.
Seemed all the rain storms of late has fired them up, another female of the 6 total adults is beginning to darken up, and commandeering the other end of the tank.
By the way Matt, I'm sorry to say I found, what I believe to be the male cardozo pike dead in the pond today. Whether or not they consummated their relationship before she took him out, is unknown at this point.