Midge · Family Chironomidae
Midge
Also called Chironomid, Buzzer, Griffith's gnat.
Short answer
Midges are tiny two-winged flies, hook size 18 to 26, that hatch in every month of the year including the coldest. On tailwaters and spring creeks they are the single most important trout food by numbers, and they are why winter fly fishing is possible at all.
What a midge is
Midges are small two-winged flies — chironomids — and they are the most numerous insect in most trout water. They matter most where other insects struggle: tailwaters with stable cold flows, spring creeks, and any river in January. The larva is a thin worm-like creature, often bright red from haemoglobin, living in the silt. The pupa rises slowly to the surface and hangs in the film, and that slow, defenceless ascent is what trout feed on most. Adults often clump together on the surface in mating balls, which is the entire logic behind the Griffith's gnat.
- Hook size
- Hook sizes 18 to 26, and smaller on hard-fished tailwaters
- Colour
- Black, grey, olive, cream and blood red
The stages trout eat
- Larva
- A thin worm in the silt, frequently red. Fished deep on a dead drift, it works all winter.
- Pupa
- Rises slowly and hangs under the film. The most eaten stage by a wide margin.
- Adult
- Tiny and hard to see. Fish take them, but rarely as reliably as the pupa.
- Cluster
- Mating balls of adults on the surface. A Griffith's gnat is a cluster, not a single midge.
When does the midge hatch?
| When | What is happening |
|---|---|
| December – February | The main event. On tailwaters this is the only hatch, and trout feed on it steadily. |
| March – May | Still heavy, now overlapping with Baetis. A midge dropper under a BWO covers both. |
| June – August | Background food. Eclipsed by bigger insects, but never absent. |
| September – November | Returning to prominence as the larger hatches fade. |
Emergence dates move with latitude, altitude and the weather of a given year. Treat these windows as a shape, not a diary, and check a local report before you travel.
Where it matters
Tailwaters and spring creeks above all — the San Juan, the Bighorn, the Missouri, the Green below Flaming Gorge, Silver Creek, the Swift in Massachusetts. Also every stillwater in the country, where chironomid fishing is a discipline of its own.
Fly fishing in New Mexico Fly fishing in Colorado Fly fishing in Arkansas Fly fishing in Massachusetts Fly fishing in Utah
How to fish it
Go smaller than you want to and fish the pupa. A zebra midge under an indicator, dead drifted close to the bottom, is the most consistently productive winter rig in America. In the film, a trailing-shuck emerger beats a dry. If you can see fish rising but cannot see anything on the water, it is midges, and you are probably two hook sizes too big.
- If fish are rising and you can see nothing on the water, it is midges.
- A Griffith's gnat imitates a cluster of adults, not one midge. That is why it can be fished large.
- Red is not a trick colour. Midge larvae really are blood red.
Flies that imitate it
Each of these is a card in the deck, and each has a full page in Our Fly-brary.
Keep reading
- Dry fly vs nymph — which stage to fish, and when
- Why trout refuse your fly — usually the wrong stage, not the wrong pattern
- Best time of day to fly fish — the daily logic behind the table above
- Our Fly-brary — every fly in the deck, explained