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San Juan Worm
A nymph, tied #8–14, carried year round. It is tied against 1 named insect in this book, and stands in when nothing is hatching — all year.
A nymph of almost no parts: a single length of red, brown or wine Ultra Chenille on a curved scud hook in sizes 8–14, its ends singed round, tied with red or brown 6/0 thread, with lead wire or a bead added when more depth is wanted. It imitates no hatching insect and points at no particular natural, which makes it a searching pattern carried through every season. Its moment is rising and coloured water. Aquatic worms live in the sediment and get washed out of it whenever the river comes up, so they arrive in the drift in numbers at exactly the times when nothing else is showing, and fish eat them without hesitation. The pattern is unfashionable and undefeated, and it is fished for trout in the same dirty push of water that puts most dry-fly plans away for the day.
- #8–14Hook size
- nymphType
- AllSeason
- 1Hatch matched
What it looks like
A drawing, not a photograph, and not traced from one. Its proportions were read off 5 independent reference photographs of the pattern and written down as 5 measured characteristics — wing angle, tail length against the shank, how far a hackle fibre reaches — every one of which had to hold across more than one of them before it could be drawn. What survives across many photographs of a fly is the fly.
What it imitates
Each of these is the same hatch record the app's own panel reads, so a pattern recommended on a river card in the app is recommended for one of the insects below.
It is also tagged for no hatch at all — a searching pattern.
Tying recipe
In tying order. This dressing is the standard one — these patterns have been in the publicrecord for decades — and materials substitute freely: the proportions and the silhouette are the pattern, not the brand of dubbing.
| Hook | Curved scud hook, sizes 8–14 |
|---|---|
| Thread | Red or brown 6/0 |
| Body | Red, brown or wine Ultra Chenille, one length, ends singed round |
| Weight | Optional lead wire or bead |
When to fish it
Rising and coloured water. Aquatic worms get washed out of the sediment and fish eat them without hesitation.
Carried all year. The insects it matches are active all year, in water from 35°F to 70°F.
Target species
- Trout
Rivers it fishes well
Rivers with a page here that sit in the regions where the insects this pattern imitates are recorded. It is a claim about coverage, not a report of a fish caught.
- Au Sable River northern lower Michigan · July mean 72.1°F
- Catawba River the North Carolina mountains · July mean 76.7°F
- Jackson River the Virginia mountains · July mean 66.3°F
- Muskegon River northern lower Michigan · July mean 71.0°F
- Escanaba River the Upper Peninsula · July mean 68.3°F
- Saint Croix River northern Wisconsin · July mean 77.2°F
- Smith River the Virginia mountains · July mean 51.9°F
- Tygart Valley River the Virginia mountains · July mean 74.6°F
- Kalamazoo River southern lower Michigan · July mean 71.3°F
- Aaron Creek the North Carolina mountains · July mean 76.7°F
- Aaron Run the Virginia mountains · July mean 77.1°F
- Aarons Run the Virginia mountains · July mean 74.2°F
Related patterns
Same type of fly, or tied for the same insects.
- Mop Fly nymph · #10–14 — Divisive and effective. Suggests a cranefly larva more than anybody wants to admit.
- Squirmy Wormy nymph · #8–14 — The San Juan with movement. For coloured, pushy water.
- Walt's Worm nymph · #12–18 — Dubbing on a hook. Suggests cranefly larvae, sowbugs and everything else pale and wriggling.
- Black Stonefly Nymph nymph · #12–18 — Dead-drifted along the bottom. Stonefly nymphs are always present in rocky water.
- Copper John nymph · #12–20 — Heavy enough to be the anchor fly. Gets the whole rig down in one cast.