Nylon or Fluorocarbon

Nylon floats better and stretches more; fluorocarbon sinks, is harder for fish to see underwater, and resists abrasion.

Nylon monofilament floats better and stretches more. The stretch absorbs the shock of a hard take and helps the tippet survive a sudden run, and the floatation keeps the leader high on the surface during the drift.

Fluorocarbon sinks, is harder for fish to see underwater, and resists abrasion. The sink rate carries the fly down in faster water, the low visibility matters when fish are wary, and the abrasion resistance helps around rocks, gravel, and timber.

Fluorocarbon tippet material came to fishing from Japanese line makers and became common in fly fishing in the 1990s. Since then it has sat alongside nylon as a standard choice rather than a specialty item.

The choice follows the water. Nylon is the default when the leader needs to stay on the surface and the take needs cushioning; fluorocarbon is the pick when the water is clear, the fish are wary, or the bottom is rough enough to nick a softer material.

Both materials carry the same X-size scale and the same pounds rating, so switching between them does not change the ÷3 hook rule — it changes how the tippet behaves in the water.

• Nylon: floats better, stretches more, cushions a hard take
• Fluorocarbon: sinks, harder to see underwater, resists abrasion
• Fluorocarbon came from Japanese line makers and became common in the 1990s
• Both use the same X sizes and pounds ratings

Further reading

• The X-Size Table
• Rig a Leader in Order