Ahhh yes pearsei, and rift lake cichlid water parameter chemistry would work well together, and because pearsei are vegetarian, any rift lake vegetarian would match any low protein food regime.
And the size differential would probably null out any territorial disputes.
Even when my pearsei hit 15"-16", they ignored much smaller fish, although in the end they easily outgrew my 150 gal tank, and had to be moved to a 300 gallon stock tank.
I wouldn't call pearsei South Ameican though, they could almost be considered N American being from Mexico, or technically speaking, Central American also living in Guatemala.