Black Ant (Formicidae)

Terrestrial, hatching June–September, active in water between 55 and 80°F, and imitated at #14–20. Recorded from 7 of the 8 regions this map covers, across Michigan, Wisconsin, Virginia and North Carolina.

A wingless worker ant, black and pinched at the waist, is not a hatch so much as a constant summer accident: it walks any bank that has trees on it, falls in, and goes down the current in numbers nobody notices. Peak is June through September, in water from 55 to 80 degrees, a band wide enough to cover cold, cold-transitional, cool and warm streams alike. The imitation runs size 14 to 20, and the single fact that governs it is that the natural sinks. An ant riding high is the wrong ant; it belongs in the film or just under it. On small, brushy water that makes it the most reliable searching pattern of the season. A Black Foam Ant or Parachute Ant in 14 to 20 covers it directly, with a Foam Beetle in 12 to 18 or a Hare's Ear Nymph in 10 to 18 as near neighbours.

#14–20Hook size
55–80°FWater, active
Jun–SepPeak months
1Life stage fished

Subbasins with trout water where it is on record: 124 of 326 across the 6 states this map draws.

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

What it is

Terrestrial · Formicidae · adult

A black terrestrial ant with a pinched waist, size 14 to 20, walking on any bank with trees on it. Wingless workers get onto the water by falling in, all summer long, in numbers nobody notices.

Sinks, so fish it in the film or just under. The most reliable summer fly on small, brushy water.

When it hatches

Peak is June–September. 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 80°F

Active from 55°F to 80°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
adult	Sinks into or just under the film — an ant riding high is the wrong ant. The most reliable searching pattern on small brushy water in summer.

Matching flies

4 patterns in this book imitate the Black Ant, 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

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.