I agree with these guys, temp change kills minnows. Check the water from your bait dealer...it's probably cold. Make him fill your bait container with his water so there's no change. I use a large ice chest for my bait chest, take it right into the store and have them fill it at least half full. Most of time I buy 10-12 dozen. Put the chest in the boat out of the way at the store and start a battery powered bubbler in there right then. When I get to the lake and my spot I grab about a styrofoam minnow bucket, fill it halfway with water, throw a few pieces of ice in there to try and make the lake water about the same temp as the cooler then put only about a dozen minnows in the styrofoam bucket. It stays beside my chair. I usually can use the dozen minnows before they run out of oxygen in the small bucket. The idea of putting a plastic drink bottle previously frozen in my large ice chest is a good idea...will start using that. Trick is too keep them at the same temp and not shock them. Course dropping them on 85 degree water on a hook kinda kicks their butt but at least they're kicking high when they go for the swim.