my lfs will take anything within 7 days for cash, 14 days for credit, and 30 days on any live fish that i just decided i didn't want as long as it is returned in same condition as purchased, a few years back i bought a fish and didn't quarantine, fish had ich, 150gal aquarium got ich, he gave me meds and offered to replace any fish that i lost, but i have been working with him for about 6 years.