Mayfly · Aquatic insect
Deleatidium / NZ Mayfly Dun
Deleatidium autumnale
Size
7–10mm
Hook size
#16–14
Hatch window
Season September–MayPeak time 11:00–17:00 (best under cloud)
Water temperature
13° peak
7°20°
Hatches from 7°C, peaking at 13°C, tailing off by 20°C.How fish feed on it
By the time the spinners are down the fly has finished its job and is simply lying there, spent, wings flat in the film, going nowhere. Trout know the difference between something alive and something that's stopped trying, and they take spinners with a quiet, unbothered sip that's easy to miss if you're still watching for something splashier. Look for them on the glides and in the slack water, wherever the current gathers what's left.
Flies that imitate this
Twilight Beauty
Adams Parachute
Deleatidium CDC Emerger
Ecology
Where you'll find this
- New ZealandPresent
Present throughout