LeechIntruder Leech
The Intruder Leech adapts the popular intruder-style shank system to create a versatile leech pattern with exceptional movement. Built on a Senyo's Micro Shank with a trailing stinger hook, this design produces a lifelike swimming action that triggers aggressive strikes from large trout and steelhead. The articulated construction allows the pine squirrel body to undulate independently for maximum fish appeal.
Year Round
Advanced
Trout, Steelhead
Dec 2025
Overview
This tightlinevideo pattern demonstrates how intruder-style construction creates superior movement in leech patterns. The trailing hook improves hookup rates on short strikes, while the articulated design allows the fly to swim and pulse naturally. The fluorescent green butt serves as a subtle attractor element without overwhelming the natural olive coloration. Pine squirrel offers excellent movement with a slimmer profile than rabbit.
Materials
Shank: Senyo's Micro Shank, 17mm
Thread: Olive, 6/0 or 140-denier
Eyes: Bead-chain eyes, black, medium
Hook: Partridge Z4 Intruder hook, #8
Connection: Braided line, 30-pound-test
Butt: Angora goat dubbing, fluorescent green
Body/Tail: Pine squirrel zonker strip, sculpin olive
Collar: Pine squirrel hair
Behavior & Presentation
Natural Behavior: Large leeches propel themselves with powerful muscular contractions, each body segment contributing to the wave-like motion that generates forward thrust. The articulated shank connection replicates this segmented swimming action authentically, allowing the trailing hook section to undulate independently while the pine squirrel zonker creates lifelike rippling along the pattern's length.
Where Trout Eat It: Predatory fish ambush this in deeper pools and undercut banks where the articulated design swims naturally.
How to Fish It: Strip, jig, or swing with variable speeds. The articulated design creates natural swimming action across techniques.
Best Water: Deeper pools and boulder pockets in moderate current where articulated movement maintains natural action.
Strike Type: Expect violent takes at the swing's terminus or during aggressive strips—the articulated design ensures solid hookups on short strikes, with fish often hooking themselves during the turn.
Fishing Strategy
Rigging Suggestions: Fish on 7-9 foot leader with 1X-2X fluorocarbon tippet. Use floating line with sink tips in rivers, full sinking lines in lake. The articulated design casts well despite its size when properly balanced.
Seasonal Timing: effectiveness with peak performance during periods when larger fish are most aggressive. and fishing can be productive with slower presentations in deeper holding water.
Pro Tips: The bead-chain eyes provide a subtle sink rate and create an up-and-down jigging action during the retrieve. The pine squirrel maintains excellent movement even at slow speeds.
Entomology
Leeches swim through water with distinctive undulating motions, contracting and extending their muscular bodies in rhythmic waves to propel themselves toward prey or new territory. Trout target these protein-rich invertebrates because they move slowly enough to be easily captured while providing substantial caloric value in a single meal.
- Organism Type
- leech
- Life Stage
- general