The pH will be at about 7.0 which I know they can live in. My real concern is will the GBR eat the other fish. In there I am going to have guppies, platies, swordtails, and mollies. The tank is going to be 55 gallons at a minimum and planted. I only plan on keeping a single pair in there. I don't think they get big enough to eat them, but I'm making sure. *PEACE!*