One of the most common food sources for fish living in rivers and streams, mayflies cannot tolerate warm or polluted water (similar to trout).

A mayfly’s life cycle progresses from Nymph → Emerger → Adult


Nearing the end of their life, adults drop their eggs into the water. The eggs sink to the bottom and hatch into nymphs. Over the course of a year (time dependent on species), the nymphs eat and grow while hiding in crevices or under rocks.


Once the nymph has packed it's bags and is ready to become a full-grown adult, they swim to the surface. Emergence is promoted by various environmental cues including water temperature and sunlight.


At the surface, a mayfly's exoskeleton breaks and a winged-form of the adult (Dun) emerges. The dun will fly away or float on the surface while it's wings dry. If the dun makes it to the bank, they will molt again becoming a spinner. Spinners then mate, lay eggs, and die. Adult mayflies live less than an hour! These "spent" flies are then gobbled up by fish.


How do I recognize mayflies?

Distinct mayfly features:

1. Watch for multiple tails (usually 2-3). Even nymphs have them!

2. Check the legs (6 of them).

3. Wings... straight up and down like a sailboat? ⛵️ Yup, its a mayfly!


Now let's talk fly imitation:

Size & Color

Most species fall inside the 10 to 18 size range and are usually olive, brown, tan, or cream in color. The best thing to do is find a nymph under a rock or snag a dun while its floating by, then compare this to the flies in your box. Try to match it the best you can.


Nymph, Emerger, or Dry Fly? Pay attention to the details...

If you see a bunch of mayflies on the water (see pictures below) and trout are sipping them off the surface, you've found the gold mine. Tie on a dry and have a blast!

If mayflies are on the water, but fish aren't quite coming up to the surface (you see their tails or fin, but not their nose/head), they are probably munching on emergers.

Nymphs are never a bad choice.

Check out some of our favorite patterns below.


We hope you found this helpful. If you have any specific follow up questions feel free to ask them through our "Contact Us" page. We are always happy to help.

Click below to check out the next major bug type—Caddisflies!