I recently purchased the portable pump that runs on 2 AA batteries. So far , I'm pleased , I keep the minnows in one of the yellow trolling buckets , and have had the same minnows since October 4th. So far , the pump appears to be capable of sustaining a dozen medium 2 inch minnows along with a dozen 1 inch. As far as time , IDK yet. I ha a few die when I let the batteries die by accident at work. I need to get rechargeable batteries for the long run , I take a lot of spur of the moment trips , and sometimes keep them in the car for brief outings before work.