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Green Rock Worm / Green Weenie (Rhyacophila spp.)
Caddis, hatching April–June and September–October, active in water between 45 and 68°F, and imitated at #10–14. Recorded from northern lower Michigan and the Upper Peninsula, where 985 Michigan rivers on this site carry a page.
- #10–14Hook size
- 45–68°FWater, active
- Apr–Jun · Sep–OctPeak months
- 1Life stage fished
What it is
Caddis · Rhyacophila spp. · larva
A bright green, clearly segmented caddis larva with a dark shiny head and a pair of hooked anal prolegs. It builds no case and carries no shelter, so it is naked on the rock and unmistakable when turned up.
The free-living larva of the green sedge, and the only caddis in these waters that builds no case — it crawls the rock exposed and is in the drift constantly. Fished dead-drift and deep, never swung. The Appalachian Green Weenie is the folk version of the same bug and outfishes far more sophisticated flies.
When it hatches
Peak is April–June and September–October. The pale months either side are the shoulder — the app widens a peak by one month in each direction and recommends the bug there, and no further: that widening is bounded so that a bug peaking in May is never offered in August.
peak shoulder not recommended
Water conditions
The band is a water temperature, not an air temperature, and it is the range in which this insect is worth fishing — for a mayfly that is the emergence window; for a scud or a midge it is simply the range trout will still eat one in.
Active from 45°F to 68°F. On this map that is cold, cold-transitional, cool water — the band crosses 2 of the three breaks the river colours use. Breaks at 58, 64 and 70°F.
Stages
What the insect is doing, and what that means for what you tie on.
| Stage | What it is |
|---|---|
| larva | Free-living, crawling over the tops of stones hunting other insects, and constantly washed loose. This is the whole of the fishing: dead-drift, deep, on a tight line. The Appalachian Green Weenie is a folk-simplified version of it, and outfishes flies with ten times the tying in it. |
Matching flies
5 patterns in this book imitate the Green Rock Worm / Green Weenie, across its stages. Which one to tie on follows the stage the water temperature says it is in — the app makes that call on a live reading; this page lists the whole set.
- Green Caddis Larva nymph · #12–16 — Bright green free-living larva. In the drift twelve months a year.
- Green Rock Worm nymph · #10–14 — Bright green segmented body, black head, curved hook. Heavier than a Green Weenie and meant to be on the bottom.
- Green Weenie nymph · #12–16 — Chartreuse chenille. Appalachian brook-trout water does not have a better fly in June.
- Perdigon nymph · #14–20 — Slim, epoxied, sinks like a stone. The euro-nymphing point fly.
- Walt's Worm nymph · #12–18 — Dubbing on a hook. Suggests cranefly larvae, sowbugs and everything else pale and wriggling.
Where to find it right now
The rivers with a page here that sit in this insect's regions, with a USGS gauge reporting water temperature. This list is re-ranked against the reading each gauge is sending now and today's date, so it is live — the fallback below it, if the readings do not arrive, is each river's measured July mean.
- Baldwin River northern lower Michigan · July mean 61.3°F
- Beaver Creek northern lower Michigan · July mean 61.3°F
- Bray Creek northern lower Michigan · July mean 61.3°F
- Coe Creek northern lower Michigan · July mean 61.3°F
- Diamond Lake Outlet Creek northern lower Michigan · July mean 61.3°F
- East Branch Hersey Creek northern lower Michigan · July mean 61.3°F
- East Branch Pine River northern lower Michigan · July mean 61.3°F
- Hersey Creek northern lower Michigan · July mean 61.3°F
- Hoxey Creek northern lower Michigan · July mean 61.3°F
- Johnson Creek northern lower Michigan · July mean 61.3°F
Regional presence
Regions, not collection records. This insect is recorded from the coarse regions below; nobody has surveyed which named river it has been caught on, and this page will not pretend otherwise.
- northern lower Michigan MI
- the Upper Peninsula MI
- northern Wisconsin WI
- the Virginia mountains VA
- the North Carolina mountains NC
Rivers in these regions with a page here
- Au Sable River
- Muskegon River
- Escanaba River
- Abitosse Creek
- Acme Creek
- Adams Creek
- Addis Creek
- Adventure Creek
- Aho Creek
- Ahola Creek
- Alabaster Whitney Drain
- Aldridge Creek
- Allen Creek
- Alward Creek
- Amundsan Creek
- Anderson Bayou
- Anderson Creek
- Anna River
- Antler Creek
- Antrim Creek
- Apple Creek
- Arsenault Creek
- Asum Creek
- Atkinson Creek
- and 961 more
Related hatches
Same family, or overlapping this one's calendar on the same water.
- Grannom Brachycentrus spp. · Caddis · April–May
- Green Sedge Rhyacophila spp. · Caddis · May–August
- October Caddis Pycnopsyche spp. · Caddis · September–October
- Spotted / Tan Caddis Hydropsyche spp. · Caddis · May–August
- Little Black Caddis Chimarra atterima · Caddis · April–May