BirdTrout
Open the map
Little Yellow Sally (Isoperla spp.)
Stonefly, hatching June–August, active in water between 55 and 68°F, and imitated at #14–16. Recorded from the Wisconsin driftless and northern Wisconsin, where 1611 Wisconsin rivers on this site carry a page.
A bright yellow-green stonefly of summer evenings, size 14 to 16, and effectively impossible to confuse with anything else on the water. The nymph is slim and amber-brown, living in riffle gravel and fished on the bottom through the summer; the adult is sulphur-yellow with the wings held flat over the back, and egg-laying females skitter at dusk, which fish answer with a splash. Broken water and the bank edge are where it shows, fluttering, and while it is on, fish rarely refuse a small yellow attractor. Activity runs with water between 55 and 68 degrees, a band spanning cold, cold-transitional and cool reaches, and it peaks through June, July and August. Nymph work falls to a Pheasant Tail in 12 to 22 or a Prince in 10 to 18; on top, a Stimulator in 8 to 16 or a Yellow Sally dressed 14 to 16.
- #14–16Hook size
- 55–68°FWater, active
- Jun–AugPeak months
- 2Life stages fished
What it is
Stonefly · Isoperla spp. · nymph → adult
The Yellow Sally: a bright yellow-green stonefly, size 14 to 16, common on summer evenings in broken water and impossible to mistake for anything else.
Bright yellow, fluttering along the bank on summer evenings. Fish rarely refuse a small yellow attractor while it is on.
When it hatches
Peak is June–August. 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 55°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 |
|---|---|
| nymph | Slim, amber-brown, in riffle gravel. Fished on the bottom through the summer. |
| adult | Sulphur-yellow, held flat over the back. Egg-laying females skitter at dusk and fish take them with a splash. |
Matching flies
5 patterns in this book imitate the Little Yellow Sally, 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.
- Pheasant Tail Nymph nymph · #12–22 — The mayfly nymph. Beadhead or not, size 16, and half the trout in the world have eaten one.
- Prince Nymph nymph · #10–18 — An attractor nymph with biot wings. Nobody agrees what it imitates and it does not matter.
- Stimulator dry fly · #8–16 — Attractor and stonefly both. Floats a dropper better than almost anything.
- Yellow Sally dry fly · #14–16 — Bright yellow, size 14, summer evenings along the bank.
- Yellow Sally Nymph nymph · #14–18 — Amber-yellow stonefly nymph. The naturals crawl to the bank to hatch, so it fishes best in close and shallow.
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.
- Black Earth Creek the Wisconsin driftless · July mean 61.6°F
- Baraboo River the Wisconsin driftless · July mean 62.2°F
- Billings Creek the Wisconsin driftless · July mean 62.2°F
- Brandy Creek the Wisconsin driftless · July mean 62.2°F
- Brewer Creek the Wisconsin driftless · July mean 62.2°F
- Cazenovia Branch the Wisconsin driftless · July mean 62.2°F
- Council Creek the Wisconsin driftless · July mean 62.2°F
- Deer Creek the Wisconsin driftless · July mean 62.2°F
- Fountain Creek the Wisconsin driftless · July mean 62.2°F
- Grinsell Branch the Wisconsin driftless · July mean 62.2°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
- southern lower Michigan MI
- the Upper Peninsula MI
- the Wisconsin driftless WI
- northern Wisconsin WI
- the Virginia mountains VA
- the North Carolina mountains NC
- southeast Minnesota MN
Rivers in these regions with a page here
- Saint Croix River
- Adams Creek
- Alder Creek
- Alder Creek
- Allen Creek
- Allen Creek
- Allen Creek
- Allen Creek
- Allenton Creek
- Allequash Creek
- Alvin Creek
- Amo Creek
- Anderson Creek
- Annis Creek
- Apple Branch
- Apple Creek
- Apple River
- Arkansaw Creek
- Armstrong Creek
- Armstrong Creek
- Arnold Creek
- Ash Creek
- Auburn Lake Creek
- Augustine Creek
- and 1587 more
Related hatches
Same family, or overlapping this one's calendar on the same water.
- Golden Stonefly Acroneuria spp. · Stonefly · June–July
- Giant Black Stonefly (Salmonfly) Pteronarcys dorsata · Stonefly · May–June
- Little Brown Stonefly Taeniopteryx / Strophopteryx spp. · Stonefly · February–April
- Little Black Stonefly Allocapnia / Capnia spp. · Stonefly · January–April
- Little Sister Caddis Cheumatopsyche spp. · Caddis · June–August