Little Brown Stonefly (Taeniopteryx / Strophopteryx spp.)

Stonefly, hatching April–May, active in water between 38 and 50°F, and imitated at #12–16. Recorded from southeast Minnesota, where 99 Minnesota rivers on this site carry a page.

#12–16Hook size
38–50°FWater, active
Apr–MayPeak months
2Life stages fished

Subbasins with trout water where it is on record: 5 of Minnesota's 72.

See Minnesota's trout water on the live map → Every reach coloured by water temperature — the water these hatches come off.

What it is

Stonefly · Taeniopteryx / Strophopteryx spp. · nymph → adult

A small, flat, brown stonefly with two tails and wings folded flat over the back. Adults are conspicuous on snow and on bridge rails in late winter, which is generally how anglers notice the hatch at all.

The earliest stonefly after the little blacks, crawling out onto snowbanks and bridge rails in late winter. Western anglers know this window as the Skwala hatch; Skwala is a Pacific-slope genus and does not occur in these states, so the eastern equivalent is these two.

When it hatches

These are Minnesota's own dates, not this site's shared calendar. They are the Early Brown Stonefly (Taeniopteryx sp.) row of Hatch Chart for Southeast Minnesota Trout Streams, Minnesota Department of Natural Resources, Lanesboro Area Fisheries (Vaughn Snook, Assistant Fisheries Supervisor), as of 15 June 2016. The chart's calendar runs January to October and makes no claim about November or December. Its own footer says it is a general time frame, that some streams have only a few of these hatches, and that others may see hatches it does not list.

Peak is April–May. 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.

JFMAMJJASOND

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.

38°F 50°F

Active from 38°F to 50°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	Crawls in gravel and leaf pack through the winter, and moves to the bank to emerge. Fishing it means fishing the edges, not the middle of the river.
adult	Emerges by crawling out, so it is on the bank and in the air before it is on the water. Egg-laying females put it there on the warmer afternoons of late February and March.

Matching flies

4 patterns in this book imitate the Little Brown 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.

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.

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

Related hatches

Same family, or overlapping this one's calendar on the same water.

Open the trout map →Every trout stream near you, coloured by today's water temperature.