Only my first year with them but would not call them vicious, definitely no worse than a rampant Parrotfinch. Had the few hectic squabbles but seem to sound worse than it is. Suppose like all birds there are different levels of temperament, had to remove a cock once because he was chasing chicks but not really any other problems. They were a lot steadier than i was expecting, lost one chick after fledgling, had a couple d.i.s. and a couple clear eggs ending up with 10 youngsters from 3 pr. My goal was a dozen but really pleased with that and on the whole found them to be great parents. Hoping for a dozen next year.