I am considering putting geos in a 75. Would that be big enough to keep a group of 4-6? The varieties I can find locally are g. juripari, brasiliensis, or maybe surimense. Forgive my spelling on the last one. I also have seen mention of g. tapajos and looked those up on net. Don't know if I can find any of those locally. Are there any other varieties out there might be good if I could find them?