Small Minnow Mayfly vs Yellow May Dun

Side-by-side species comparison

Attribute Small Minnow Mayfly Yellow May Dun
Scientific Name Callibaetis ferrugineus Heptagenia sulphurea
Order Ephemeroptera Ephemeroptera
Family Baetidae Heptageniidae
Size 7-11 mm 10-15 mm
Habitat Ponds & Lakes Rivers & Streams
Diet Detritivores Omnivores
Regions North America Europe
Conservation Least Concern Least Concern

Small Minnow Mayfly

A mottled brown mayfly common in still waters across North America. Nymphs are excellent swimmers that mimic small minnows.

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Did You Know?

It can produce up to three generations per year in warm climates.

Yellow May Dun

A bright sulfur-yellow mayfly common across European rivers during early summer. Its flat nymphs are adapted to fast-flowing water on stony substrates.

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Did You Know?

The striking yellow color of this mayfly makes it one of the most easily recognizable species on European rivers.