If water is soft, acidic, temp's 82 to 84 degrees F ,the German blue ram's may thrive depending on stock aquired.
Many of these fishes that are imported, are reportedly kept in water's loaded with antibiotic's and other chemical's,hormones, to induce nice color's,ward of bacterial pathogen's.
Once fish are removed from these water's and then shipped to store's from possibly thousand's of miles away,,acclimated to store tank's,your tank,my tank, more than a few succumb in a matter of a few week's.
Might try and find breeder that can verify the fish are being raised in close to same water as you have.
You mention a pair.if breeding is the aim,,I would submit that the Goby,Angelfish,platy's,(platy's need hard alkaline water,)would happily eat any fry should the ram's produce successful spawn.