Keeping Guppies alive
How long has your tank been set up? Do you have live or fake plants? What do the guppies tails lool like when the die? Do they look whole and long, or ragged and shorter than when you got them home?
Are all guppies dead, just males or just females?
Guppies are hardy enough that they should be ok in an estrablished tank, even with some elevated water test levels. I would expect the other fish to go first. Now, do you float the bag when you get them and net them out, pour them and the water in tank, or add tank water to the guppy water over a few hours....
It all ads to the story, and explaination. :)