No offense, but I would say a bigger tank. Those zebras grow fast, get over 6" and are going to tear each other apart (if they're not already). Like most other cichlids, pretty sure that greshakei males will not discriminate in who they go after... normal coloration or albino.
Suitable tank mates for these bruisers would be johanni, red zebra, auratus.. other fish high on the aggression chart.