You can leave them in your live-well on they way home no problem for a 20 minute ride. Just make sure you are circulating the water while on the lake and prior to leaving. If you are putting them in a bucket I would get fresh water in there prior to putting the fish in and they should still be okay as long as water temps are not 90 and its 100 outside. You can also add ice to live-well or the bucket just to cool water down some. Really it depends so much on ambient temp and water temp you are using. Today its 80 but water is still cool. June its 90 water temp and 100 outside they aren't going to last long in that.