If two of the CONS pair up and start breeding, it's game over for the Labs. Take it from me, I had a breeding pair of CONS in one tank and Africans in another. Well, I had aggression problems with a mean as **** Tropheus (killed my Mbuna and Haps) in the African tank, so I moved it into the Convict tank. The Tropheus started trying to bully around the CONS, started with my small Pink female, then the large Black male CON layed into the Tropheus. The Tropheus put up a good fight, but ultimately the CON was too much. I didn't want the Tropheus to die, so I gave it to guy with a 55gallon with about 10 adult Mbuna. The Tropheus did great in that tank, wan't aggressive at all. Sadly he lost power one day and everyting but two Mbuna and his Lelupi died. Here I thought I did the fish a favor, only to die a few months later anyways. Now one CON by itself may get destroyed by a group of Labs.