I hear you on the beating but at what age/size roughly do they begin breeding. My guess is around 5-6" for a fish this size??
When I've bred large african's 12"> they have left the loaches alone except to skirt them away from a breeding site. Is your warning because of the total area these fish take over as a breeding site? Or vieja's just get that nasty? I have seen a pair of Festae's breed and that was something to behold as far as aggress goes but I did not think these were that bad from what I've read. I also know this is a hybrid so all bets are off.
I am not really looking to breed this fish but he seems to already have a GF
It also seems that these fish at this size like to be over stocked like a Mbuna tank to reduce aggr.
Steve
Fish can snap at any time.. I know Cyano/Carpintis guard their nesting sites like a fat kid protects his cake. You can never really know with these hybrids..