Midge · Aquatic insect
Reed Smut
Simulium ornatum
Size
2–4mm
Hook size
#22–20
Hatch window
Season May–SeptemberPeak time 11:00–15:00
Water temperature
15° peak
10°22°
Hatches from 10°C, peaking at 15°C, tailing off by 22°C.How fish feed on it
This is the one where the textbook gets it backwards: for a reed smut the adult is the whole problem, not an afterthought behind some more important earlier stage. Dense swarms of females return to lay on the surface of fast chalk-stream and freestone water through summer, and trout key onto something so small — barely visible at 2 to 4mm — that the rise looks absurdly gentle and confident, sipping steadily in one spot without ever seeming to move for anything larger. This is smutting, and it has driven anglers on the Test and Itchen to quiet despair for longer than anyone alive has been fishing them: match the size, not the pattern, and expect it not to work first time anyway.
Flies that imitate this
Reed Smut
Black Gnat
Griffith's Gnat
CDC Midge Cluster
Ecology
Where you'll find this
- British IslesPresent
- IberiaPresent
- The AlpsPresent
- ScandinaviaPresent
- Continental EuropePresent
- Atlantic fringePresent
- North America — WestPresent
- North America — EastPresent
- East AsiaPresent
- New ZealandPresent
- PatagoniaPresent
Present throughout