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Little Black Stonefly (Allocapnia / Capnia spp.)
Stonefly, hatching January–April, active in water between 34 and 46°F, and imitated at #16–18. Recorded from the Virginia mountains, where 796 Virginia rivers on this site carry a page.
The first insect of the year: small, black, size 16 to 18, crawling on snow along the bank in February while the river is still icing over at the edges. The peak runs January through April, in water from 34 to 46 degrees — the cold class alone, and no other. The nymph is small, dark and slim, living in gravel and available all winter, which matters more than the hatch itself does. The adult crawls out onto snow and ice to emerge, and egg-laying on mild midwinter afternoons brings the first surface feeding of the year; it is the only dry-fly hatch most winters offer. A Black Stonefly Nymph at 12 to 18 covers the subsurface stage, with a Prince Nymph, 10 to 18, as a stand-in. On the surface a small dark dry serves: an Elk Hair Caddis at 12 to 20 or a Griffith's Gnat at 18 to 24. The records span a wide northern and Appalachian area without fixing the insect to any particular water.
- #16–18Hook size
- 34–46°FWater, active
- Jan–AprPeak months
- 2Life stages fished
What it is
Stonefly · Allocapnia / Capnia spp. · nymph → adult
The first insect of the year. Small, black, size 16 to 18, crawling on snow along the bank in February while the river is still icing over at the edges.
Crawls out onto snow and ice on the first mild day of the year. The only dry-fly hatch most winters offer.
When it hatches
Peak is January–April. 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 34°F to 46°F. On this map that is cold water. 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 |
|---|---|
| nymph | Small, dark and slim, in gravel. Available all winter, which matters more than the hatch does. |
| adult | Crawls out onto snow and ice to emerge. Egg-laying on mild midwinter afternoons brings the first surface feeding of the year. |
Matching flies
5 patterns in this book imitate the Little Black Stonefly, 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.
- Black Stonefly Nymph nymph · #12–18 — Dead-drifted along the bottom. Stonefly nymphs are always present in rocky water.
- Early Brown Stone Nymph nymph · #12–16 — Brown, flat, two-tailed and small. The only thing moving on the rock in February and March.
- Elk Hair Caddis dry fly · #12–20 — Floats forever, skates on command, works when nothing is hatching.
- Griffith's Gnat dry fly · #18–24 — A cluster of midges in one fly. The winter dry, and the answer to unexplained sippers.
- Prince Nymph nymph · #10–18 — An attractor nymph with biot wings. Nobody agrees what it imitates and it does not matter.
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.
- Als Run the Virginia mountains
- Alum Creek the Virginia mountains
- Anderson Run the Virginia mountains
- Ararat River the Virginia mountains
- Auberry Creek the Virginia mountains
- Back Fork the Virginia mountains
- Back Run the Virginia mountains
- Baker Branch the Virginia mountains
- Baldwin Branch the Virginia mountains
- Baldwin Branch the Virginia mountains
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
- southern lower Michigan MI
- the Upper Peninsula MI
- the Wisconsin driftless WI
- the Virginia mountains VA
- the North Carolina mountains NC
- southeast Minnesota MN
Rivers in these regions with a page here
- Jackson River
- Smith River
- Als Run
- Alum Creek
- Amos Branch
- Anderson Run
- Ararat River
- Auberry Creek
- Back Creek
- Back Creek
- Back Fork
- Back Run
- Baker Branch
- Baldwin Branch
- Baldwin Branch
- Barbours Creek
- Bark Camp Branch
- Bark Camp Branch
- Barkcamp Branch
- Barnard Creek
- Barney Run
- Barterbrook Branch
- Batie Creek
- Battery Creek
- and 772 more
Related hatches
Same family, or overlapping this one's calendar on the same water.
- Little Brown Stonefly Taeniopteryx / Strophopteryx spp. · Stonefly · February–April
- Little Yellow Sally Isoperla spp. · Stonefly · June–August
- Golden Stonefly Acroneuria spp. · Stonefly · June–July
- Giant Black Stonefly (Salmonfly) Pteronarcys dorsata · Stonefly · May–June
- Blue-Winged Olive Baetis spp. · Mayfly · March–May and September–November