Some of you people need to do a little research as far as fish compatability. Of course the fish are agressive you put them in a small glass box. In a big lake this would never happen as the fish that is picked on would just swim away. Read up on a particular fish before you purchase!
All these cichlids are nasty. Give them a target inside their territory and it's like that. They are aggressive and mean in their own ways.
A jewel might be more aggressive than a dovii if the dovii is smaller than the Jewel being its target in the glass box. But the Dovii would eat or destroy the Jewel if it wasnt smaller or out of baby stage