Gotta watch wally world fish. My kids have tried there 4 times (pets) and each time they end up dieing from some fungus that attacks the slime and gills of the fish...
Best to go to a proper "fish store"
Point being you may not want to introduce them into a pond and spread a contamination.
It could be no big deal too. It may not be able to fungus up other fish in a lake setting.... I just don't know.
Good Advice Big Bro ( CJD ). Also if you are going to use them for bait don't tell the Petco guys, they may cut you off. My uncle had paronias years ago and feed them gold fish, the guy at the pet asked him one day why he was buying so many gold fish, he told them and the store cu him off, lol.