Okay so the Metriaclima estherae is a total bully. I picked up another of his kind which he chased almost to death. He was picking on the 3 3" electric yellows before but not as much now, possibly cuz hes been chasing the other all night. Do I need more than 5 cichlids to spread out the aggression? I don't want to watch fish get beaten to death If so, what would make a good (colorful) addition?? & should i take size into consideration when selecting??