In this order.....H. Faciatus...(some call them H. Frembongi now-a-days)
Dovii...then Umbie.......
If a Zaliosum wasn't "outgrown" by all the others, it would be the meanest of all.....
However...I'm old....I've raised all kinds of aggressive cichlids for over 35 years....and
though I know a helluvalot about big, mean, aggressive cichlids, I still learn something new everyday....and, I've been told some of the flowerhorns are extremely aggressive too...??
But, from my experience, and I have alot....the H. Faciatus is the strongest toughest cichlid there is when full grown....but it's not always the case....I have a 15 inch Red Devil, quad colored, that runs my 17 inch butter, my 10 inch dovii and my umbee under rocks.....but he's beserck and not mentally stable....LOL