Shouldn't be a problem in a 56, why don't you pair up the Bolivian rather than adding another type of Ram. Ive found keeping the Bolivians much more interesting and fun compared to GBR, as much as GBR are a lovely fish they don't go long in my tank before I'm separating them or rearranging the tank due to disputes during breeding, it can become a pain at times. I've only one pair of them now in with a few other dwarf cichlids and life is much easier on me and tank mates, and when they eventually go I think I'm through with the GBR's, though I still might set them up in a tank just for GBR.