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Little Black Caddis (Chimarra atterima)
Caddis, hatching April–May, active in water between 46 and 58°F, and imitated at #16–20. Recorded from northern lower Michigan and southern lower Michigan, where 614 Michigan rivers on this site carry a page.
A small, very dark caddis — nearly black body, dark grey wings, size 16 to 20 — that comes off in the same cold weeks as the Hendrickson and is easy to write off as a midge. The peak is April and May, in water from 46 to 58 degrees, which covers only the cold and cold-transitional classes. Chimarra spins a fixed net on rocks in fast water rather than carrying a case, so the larva stays put in the current. The pupa rises fast to the surface, and the swung wet is the classic answer to it. The adult is dark, small and skittering, present in numbers on April afternoons. A dark soft-hackle swung on the tail of a run is the simplest way to fish the emergence: a Partridge and Orange Soft Hackle at 12 to 18 does that work. A CDC Caddis, 14 to 20, or an Elk Hair Caddis, 12 to 20, covers the adult, and a Zebra Midge at 18 to 24 sits alongside for the confusion the size invites.
- #16–20Hook size
- 46–58°FWater, active
- Apr–MayPeak months
- 3Life stages fished
What it is
Caddis · Chimarra atterima · larva → pupa → adult
A small, very dark caddis — nearly black body, dark grey wings, size 16 to 20 — that comes off in the same cold weeks as the Hendrickson and is easy to write off as a midge.
Small, dark, and everywhere in April. A dark soft-hackle swung on the tail of a run is the easy way to fish it.
When it hatches
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.
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 46°F to 58°F. On this map that is cold, cold-transitional water — the band crosses 1 of the three break 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 | Chimarra spins a fixed net on rocks in fast water rather than carrying a case. |
| pupa | Rises fast to the surface. The swung wet is the classic answer. |
| adult | Dark, small, and skittering. Present in numbers on April afternoons. |
Matching flies
5 patterns in this book imitate the Little Black 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.
- CDC Caddis dry fly · #14–20 — Lower in the film than an Elk Hair. For flat water and educated fish.
- Little Black Caddis Pupa emerger · #16–20 — Dark body, sparse soft hackle. Swung through the tail of a run in April, which is where the naturals are going.
- Elk Hair Caddis dry fly · #12–20 — Floats forever, skates on command, works when nothing is hatching.
- Partridge & Orange Soft Hackle wet fly · #12–18 — Swung down and across. The simplest fly here and among the most effective.
- Zebra Midge nymph · #18–24 — Two materials and a bead. The winter fly, and the fly for the last two feet of a tailout.
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.
- Allen Creek northern lower Michigan
- Antrim Creek northern lower Michigan
- Bartholomew Creek northern lower Michigan
- Bassett Creek southern lower Michigan
- Battle Creek northern lower Michigan
- Bear River northern lower Michigan
- Belangers Creek northern lower Michigan
- Bennett Creek northern lower Michigan
- Bissell Creek northern lower Michigan
- Black River southern lower Michigan
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 Wisconsin driftless WI
- the Virginia mountains VA
- the North Carolina mountains NC
- southeast Minnesota MN
Rivers in these regions with a page here
- Au Sable River
- Muskegon River
- Kalamazoo River
- Acme Creek
- Adams Creek
- Addis Creek
- Alabaster Whitney Drain
- Allen Creek
- Anderson Bayou
- Antler Creek
- Antrim Creek
- Apel Drain
- Apple Creek
- Asum Creek
- Atkinson Creek
- Au Gres River
- Au Sable Creek
- Augusta Creek
- Backus Creek
- Baker Creek
- Bakers Creek
- Baldwin River
- Bamfield Creek
- Bancroft Noles Drain
- and 590 more
Related hatches
Same family, or overlapping this one's calendar on the same water.
- Grannom Brachycentrus spp. · Caddis · April–May
- Green Rock Worm / Green Weenie Rhyacophila spp. · Caddis · April–June and September–October
- Spotted / Tan Caddis Hydropsyche spp. · Caddis · May–August
- Green Sedge Rhyacophila spp. · Caddis · May–August
- Little Sister Caddis Cheumatopsyche spp. · Caddis · June–August