The Neilsen Automatic Feeder was a common tool used at fish hatcheries for several decades. The feeder could hold 12 pounds of dry pellet feed and an adapter increased the capacity to 50 pounds. A fan at the bottom of the feeder spread the feed over a large area of the water surface. A clock on the feeder allowed hatchery staff to schedule feedings throughout the day to acquire the desired growth rate of the fish being reared.