I think the missioneira's max out around 7-9" so your lent would likely abuse them.
I put these pikes in my 92g corner tank, which I've gradually making a South American theme. That said, I have a pair of siquia convicts (convict cousin actually). The largest male pike seriously underestimated the male convict - the pike learned the hard way.
The siquia pair are moving to another tank soon and I may use the fry to feed the pikes...if my wife doesn't notice ;-) Then the pikes will be happy...