I think you should return the fish and let your tank cycle. What kind of filtration are you using? How long has your tank been running? You are going to run yourself ragged changing the amount of water you need to change daily to keep these fish safe. Do yourself a favor and return the fish or find a temorary tank that is cycled that you can keep them in untill yours is cycled. Let your tank cycle completely! There are some good stickys on here about the cycle and will explain it. Read read read.