Its all about tank size.
I grew out some dovii in a 150 gallon with other cichlids, and it was fine until the dovii hit about 6 inches.
At that point "they" seemed to perceive there was not enough space and it showed in the form of aggression.
And when in a 1,000 gal enclosure, aggression subsided.
If you check out videos off Mel's dovii on youtube, in 500 to 1,000 gal tanks, they are quite docile, and sub-Dude.