Large Dark Olive Mayfly vs March Brown Mayfly

Side-by-side species comparison

Attribute Large Dark Olive Mayfly March Brown Mayfly
Scientific Name Baetis rhodani Rhithrogena germanica
Order Ephemeroptera Ephemeroptera
Family Baetidae Heptageniidae
Size 6-10 mm 10-14 mm
Habitat Rivers & Streams Rivers & Streams
Diet Omnivores Omnivores
Regions Europe Europe
Conservation Least Concern Near Threatened

Large Dark Olive Mayfly

The most common European mayfly, emerging year-round in many rivers. It is a small olive-brown species that serves as a staple food for stream fish.

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Did You Know?

This mayfly can produce up to three generations per year, making it available as fish food in every season.

March Brown Mayfly

A spring-emerging mayfly with a brownish body and two tails, historically important to European fly fishing. Its flat nymphs cling to rocks in fast water.

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Did You Know?

This species has declined significantly in many European rivers due to pollution and is now considered an indicator of water quality.