It depends on the severum really, they can differ very much in attitude and aggressiveness Sevs are big pussycats...dothedew said:Most sevs get very aggressive with other cichlids after a few months. I hear a lot of stories about them beating up Oscars (I think vip said this) and blood parrots. I wouldn't attempt to mix the two.
Vip, like dwarfs said, usually sevs don't reach a foot.
 he's the biggest one in there. Hopefully my surinam geo will take over after he outgrows the sev. Severums aren't too aggressive compared to other cichids though