Aw poor guy.. :(
I think Petsmart has a more lenient policy with its 15 day guarantee or something like that. They don't ask for a water sample because it's part of their no questions asked policy or something like that. At least I think its petsmart.... o-o
For petco I think its 14 days....
If you have a reciept it has the info on the back; you just have to find the part referring to live fish.