Mayfly · Aquatic insect
Medium Olive
Baetis vernus
Size
6–9mm
Hook size
#16–14
Hatch window
Season April–JulyPeak time 12:00–16:00
Water temperature
13° peak
8°19°
Hatches from 8°C, peaking at 13°C, tailing off by 19°C.How fish feed on it
A modest fall over the flats. Rarely the making of an evening, but worth recognising when the duns have stopped and fish are still up.
Flies that imitate this
Klinkhåmer Special
CDC Olive Emerger
Greenwell's Glory
Waterhen Bloa
Ecology
Where you'll find this
- British IslesPresent
- IberiaPresent
- The AlpsPresent
- ScandinaviaPresent
- Continental EuropePresent
- Atlantic fringePresent
Present throughout
About the genus Baetis
Baetis is a genus of mayflies of the family Baetidae, known as the blue-winged olive to anglers. There are at least 150 described species in Baetis . They are distributed worldwide, with the most variety in North America and northern Europe.