In warmer weather best way to keep shiners/minnows alive is to use a aerator and fill a couple 16 oz. Plastic coke bottles with water and freeze. Never add ice directly to the water in the bucket. Put the frozen bottles with the cap on tight into the bucket and they will last a lot longer. Put one bottle in bucket at a time. Once one bottle turns to mostly water take it out and add other bottle which i keep in my drink cooler with my other drinks. This has worked really well for me on those warm/hot days when i want to fish with minnows/shad.