Mayfly · Aquatic insect
Mayfly (Green Drake)
Ephemera danica
Size
15–25mm
Hook size
#12–10
Hatch window
Season May–JunePeak time 12:00–17:00
Water temperature
15° peak
10°20°
Hatches from 10°C, peaking at 15°C, tailing off by 20°C.How fish feed on it
The spent gnat is the part that actually catches the biggest fish, and the part most people leave too early to see. After the dance, the females fall dead in the surface with their wings flat out, and a trout that ignored the duns all afternoon will settle into a quiet, methodical patrol picking them off. Evening, flat water, and no hurry about any of it.
Flies that imitate this
Green Drake
Grey Wulff
Spent Gnat / Spent Mayfly
Shadow Mayfly
Ecology
Where you'll find this
- British IslesPresent
- IberiaPresent
- The AlpsPresent
- ScandinaviaPresent
- Continental EuropePresent
- Atlantic fringePresent
Present throughout
Identification
Ephemera danica is a species of mayfly in the genus Ephemera .