Byford's Natural Zonker - Zonker. The American Fly Fishermen that developed the first Zonker was named the Dan Byford, creating a imitation of a small bait fish. This imitation is a close replication of the first zonker. The Byford's Natural Zonker works best when the sun is off the water, therefore early morning and evening seem to be the best times for the Byford Natural Zonker. Fish the Byford Natural Zonker up stream as this most accurately mimics the movement of real baitfish.