Lateral view of a Female Hexagenia limbata (Ephemeridae) (Hex) Mayfly Dun from the Namekagon River in Wisconsin

Hex Mayflies
Hexagenia limbata

The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.

A small, old rock wing dam has created an excellent riffle and pool in this classic trout stream.

Stream photos

Featured on the forum

Re: Trico emergers
In the Mayfly Genus Tricorythodes by Bwoklink (Martinlf replied)

Re: Trico Tips
In the Mayfly Genus Tricorythodes by Martinlf

Re: UV spectrum and trout
In General Discussion by Martinlf

Re: closing the gender gap in flyfishing
In General Discussion by Konchu (Smallflyguy replied)

Re: Fishing Kupa River, Slovenia
In Fishing Reports by Slocum (Fish1 replied)

Male Baetidae (Blue-Winged Olive) Mayfly Dun Male Baetidae (Blue-Winged Olive) Mayfly Dun

Lateral view of a Male Baetidae (Blue-Winged Olive) Mayfly Dun from Mystery Creek #308 in Washington

This dun emerged from a mature nymph on my desk. Unfortunately its wings didn't perfectly dry out.

7 Recently Added Photos

27" brown trout, my largest ever. It was the sub-dominant fish in its pool. After this, I hooked the bigger one, but I couldn't land it.

Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or support the project for an enhanced experience here.

Mayfly Genus Anthopotamus (Golden Drakes)

These mayflies have something for everyone. For the angler, they offer a chance to fish large dry flies to a rise on midsummer evenings when little else is on the water. To the entomologist they are interesting for their unique placement mid-way between the burrower and crawler groups of nymphs. Another curious characteristic is that the eyes of the adults are the same size in both genders; this is very unusual in mayflies.

Where & when

Time of year : Late June through August

Preferred waters: Mostly medium to large rivers

See the individual species pages for distribution and timing details. Anthopotamus distinctus is the main species in the East, and Anthopotamus myops is more common in the Midwest.

In 99 records from GBIF, adults of this genus have mostly been collected during June (48%), July (34%), and August (12%).

In 34 records from GBIF, this genus has been collected at elevations ranging from 618 to 5003 ft, with an average (median) of 3133 ft.

Genus Range

source

Map of specific collection sites

Hatching behavior

Time of day : Throughout late evening, peaking at dusk, sometimes after dark on hot days.

Habitat: Slow to medium water

Water temperature: 65-70°F

These mayflies emerge fairly quickly, but they may linger on the surface for a while as their wings dry, making dun patterns the imitation of choice. They can make some commotion which is worth imitating if a still pattern does not work.

Caucci and Nastasi in Hatches II say that the duns begin hatching when the temperature drops below 70°F in the evenings. However, in Matching the Hatch, Ernest Schwiebert reports a hatch when the water temperature was a steamy 78°F. The trout are unlikely to respond at such times.

Spinner behavior

Time of day: Twilight to late night

Ted Fauceglia writes in Mayflies that the best trout activity associated with these spinner falls happens well after dark. This is the only mention of fishing to the spinners that I've found.

Nymph biology

Current speed: Slow to Medium

Substrate: Detritus over sand, gravel, or silt

Environmental tolerance: They have an unusually high tolerance for warm, shallow water.

The nymphs of this genus are the unique representatives of a transitional step between the crawler nymph group and the burrower nymphs. They don't dig U-shaped burrows into the sediment like Ephemeridae nymphs do, but they do settle down into indentations in the detritus.

They become active on the bottom shortly before emerging, and fishing nymph imitations before the hatch may reward the angler.

Start a Discussion of Anthopotamus

References

Arbona, Fred Jr. 1989. Mayflies, the Angler, and the Trout. Nick Lyons Books.
Caucci, Al and Nastasi, Bob. 2004. Hatches II. The Lyons Press.
Fauceglia, Ted. 2005. Mayflies . Stackpole Books.
Knopp, Malcolm and Robert Cormier. 1997. Mayflies: An Angler's Study of Trout Water Ephemeroptera . The Lyons Press.
Schwiebert, Ernest G. 1955. Matching the Hatch. MacMillan Publishing Company.