Large dark olive
Baetis rhodani
Window
Typical: 25 Mar – 15 May (2026)
Early-season trotting fly. Mid-morning hatches on calm cool days.
Relevance to fishing
First serious upwing hatch of the year on chalk streams and rivers. Trout and grayling come up to it; a dry-fly opener.
Phenology chain
No chain links seeded for this event yet.
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Observation history (0)
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