Trout Stream's Strongest Bead Head Caddis Fly - 12 Flies - For Tenkara, Nymphing, Iwana, Amago, and Yamame Perfect for those targeting rainbow trout, Iwana, Amago, and other trout species in managed fishing areas, streams, and lakes. While it can't beat real caddisflies, it often yields good results in streams. Also, since real bait doesn't last long, these are convenient to keep on hand and are a recommended product. Please give them a try. The hook size is #12, but it can also be changed to #8 or #14. Thank you.