As mentioned, brasiliensis and steindachneri (and the closely related species of both, iporogensis etc.) can have mean streaks, brasiliensis moreso as they can't really be referred to as a normal eartheater.
Keep in mind that males of most species will show some signs of aggression, however they don't have the mouth to back up the flare, and it will usually only be conspecific targets (other Eartheaters). Eartheaters like chasing other Eartheaters, but in my experience its different to other Cichlids in the fact that they have chasing bursts here and there but it never affects their activity or lasts longer than 15 seconds or so, whereas more standard Cichlids will learn to hate or fear aggressors.
With that said, they're Cichlids. Every single one is different.