ive kept a few saums, but never in large quantities. never bred them either. they were in mixed tanks with JDs, oscars, pacus, texas, etc. Thats not a good comparison to the GT community tank i have now. They can all be mean when they want to, but my experience is that they just go with the flow. if the tank is at peace, they are at peace. if fish are establishing territories, the GT/Saum is gonna stake their turf.