on here there may not be any experience, but on the puffer forum they had a experienced member try to breed fahaka's once... long story short, they beat the crap out of each other THROUGH a heavily locked in divider, one was manned real bad and the jumped out the tank... both ended up dead...
So in short, never ever try to keep two together unless you maybe have a 3000+ Gallon tank then MAYBE, and only maybe they might just get along...