If you are not familiar with cycling, you really need to be to keep your fish alive. Here's a good place to start:
http://www.fishlore.com/Forum/index.php?topic=620.0
For any fish to stay healthy, you need:
Zero Ammonia
Zero Nitrites
Zero to 20 Nitrates
Ph is not usually an issue unless you have one that's not stable, you keep wild caught fish, or you are breeding fish
Water Hardness is also not something that is usually important except if you have a high tech planted tank, and for some species of fish
Zero Chloramine/Chlorine You should always treat for chlorine and chloramines each time you add new water to the tank unless you have well water
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