Minnow Mayfly Nymph

Statistics

Taxonomic order: Ephemeroptera

Taxonomic family: Baetidae

Length: up to 1.5 cm

Average life span: 1 to 2 years

Juvenile stage (in water): up to 2 years

Adult stage (out of water): up to 2 days

When To See

All year.  These mayflies are tolerant to temperature fluctuations and can overwinter as active and growing nymphs.

Photo credit: lifeinfreshwater.org, Iain Reid

Habitat

Baetid nymphs are widespread and can be found in a variety of freshwater habitats. If conditions permit, they occur in large numbers. Some species can be very common in polluted and low oxygenated waters. They feed on plant matter, organic detritus and algae by scraping solid surfaces or collecting from the sediments.

How To Identify

Rounded head, with a pair of antennae two or three times longer than the width of the head. Oval or leaf-shaped plated gills on the side of the abdomen. Three long hairy filaments (setae) at the end of the body. Brownish or greenish colour.

Seen It?

Been kicking about in your local river and come across one of these invertebrates? Not sure? Share it with us at trust@forthriverstrust.org, we enjoy chatting about inverts with you.