Wow really Tony? I figured they were just a typical big fish eats little fish kind of predator. What ranks above those guys on your top 3?
They're the worst of the Nimbochromis for sure. Had mean venustus before, but not like those guys. I think they're on that border between Nimbochromis and Tyrranochromis - a much more aggressive genus.
The other two most angry Malawi haps (that I've kept as adults) would be Tyrranochromis nigriventor and Buccochromis nototaenia. Attitude + size + capable mouths put those guys up there with some of the centrals in terms of ability to take out tankmates.
All three of those fish get large. I have seen the first two at a foot long and they are big heavy fish. The Shed Aquarium has a B. nototaenia that must be in excess of 20".... an absolute monster who keeps a foot long venustus pinned under a rock all day.
For other meanies I've kept, my honorable mention would have to go to Naeviochromis chrysogastor. The are egg stealers in the wild, so are all about whacking each other in the face. I *had* a very nice W/C group that dwindled over time as they beat the hell out of each other.
In the absence of females and in a large tank (180+), adult aggression could be kept lower, but definitely try to avoid conspecifics as an extra safety measure.
There is a reason that I don't keep many predatory haps anymore...
