Yes, usually chain stores (petsmart, petco and walmart) will get already sick ones or they will get ill and die days after being bought. Fighters are usually weaker due to the inbreeding.
Peanut was bought on Saturday, was sent out on monday, delivey next day was postponed and arrived to me on wednesday morning before i had to go school and was still in perfect condition when i cames back from school, but only very stress.
When i acclimate him to his new home he was quite nervous and was darting and exploring every where and nver scare of my finger or whole hand unless out in the tank LOL.
Stuck in the mail for one weeks? Is it okay?