A Frabill portable bait aerator (about $15) not only can keep minnows alive indefinitely, it can solve problems relating to transporting water in this age of aquatic invasive species. Buy your minnows in an oxygenated, water-filled bag. Keep the bait in the bag, placing it in a 5-gallon bucket. Hook the battery operated aerator on the bucket and start it. No need to add water all day long.
DENNIS ANDERSON