About how long will a dozen minnows last in a non aerated cooler? It takes me about 45 min to get from where I get them to where I fish. I can buy them where I'm fishing but for 5$ a dozen I'd rather catch them in the river close to my house. Why don't I fish the river near my house you may ask; it's fished heavily as it runs through town and no big fish.

depending upon the size of the cooler, and the size of the minnows.  It is a rather inexpensive undertaking to add aeration to your bucket, and would probably give the best results for keeping your bait frisky.  It also dosent hurt to add a bit of ice to the bucket as well.  Fish being cold blooded use less oxygen in cooler conditions, and also cooler water holds more oxygen that warm.

Hope this helps

Recon

If you leave them in a plastic bag and blow the bag up with oxygen..put them in your cooler or baitwell/livewell..they will last 8 hours.

Thanks guys. I just orderd an aerator from Cabelas. It's a small one but I have a 10 gallon Igloo Industrial water cooler I'm going to convert into a livewell for home. Hopefully I will be able to keep the minnows alive for about a week by adding ice until I'm ready to go fishing then put them into the smaller aerator. You think this will work?