Certain Altifrons are aggressive. It really depends on the fish itself. Was your Altifrons attacking your Balzani? How many of each do you have?
My most aggressive geo is Tapajos II. My largest male ripped off one of my females eyes. I had two breeding pairs together. And the female that wasn't paired with my largest male was the victim. Needless to say, each pair has their own tank now.
My most peaceful are my Tapajos 'Orangeheads'.