Go to Walmart and buy one of the medium sized rectangular coolers(usually $12 - $15). I drill a hole in the back of the cooler up towards the top big enough to slide aquarium air tubing thru. You can then run an air pump, portable or 12v and keep the minnows alive all day... But you have to be sure to change the water every day or so or they will die from ammonia build up... We spider rig and when we buy minnows, we buy 1 1/2 pounds usually... They will be very lively at the end of the day and make it home to be added to the minnow tank for the next trip to the lake.... On really hot days the cooler will keep them cool as long as you keep the lid closed.... You can also freeze 16oz bottles of water and slip one in there on the reaallly hot days...