Spotted / Tan Caddis (Hydropsyche spp.)

Caddis, hatching May–July, active in water between 55 and 70°F, and imitated at #14–18. Recorded from southeast Minnesota, where 99 Minnesota rivers on this site carry a page.

#14–18Hook size
55–70°FWater, active
May–JulPeak months
3Life 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

Caddis · Hydropsyche spp. · larva → pupa → adult

Hydropsyche: the commonest caddis on most of this water. A tan to cinnamon tent-winged adult, size 14 to 18, with a net-spinning larva that lives everywhere there is current.

The workhorse summer caddis. A net-spinner, so it is in the drift year-round even when nothing is on the surface.

When it hatches

These are Minnesota's own dates, not this site's shared calendar. They are the Spotted Sedge (Hydropsyche slossonae) 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 May–July. 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.

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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.

55°F 70°F

Active from 55°F to 70°F. On this map that is cold, cold-transitional, cool, warm water — the band crosses 3 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	Spins a net in fast water to strain drifting food. Constantly dislodged and constantly eaten — a green or tan caddis larva is a default nymph.
pupa	Rises to the film in the evening. A swung pupa is the most reliable way to fish this hatch.
adult	Tan, tent-winged, and everywhere from May through August. Egg-layers dive and skitter, which a dead drift does not imitate.

Matching flies

6 patterns in this book imitate the Spotted / Tan Caddis, 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.