Scientists scooped sand from a riverbed in Thailand and found two nymphs of rare mayfly species not seen in 22 years, a study said. Photo from Kwanboon and Boonsoong (2025) Knee-deep in a river of ...

Fly anglers should have a basic understanding of the four stages of a mayfly’s life cycle. It starts with eggs laid on the water’s surface. Those eggs sink and eventually hatch into nymphs.