Other Common Name: Brown dun
Scientific Name: genus Ameletus

Ameletus nymphs are swimmer-type mayflies that are most often found in the fast, cold headwaters sections of mountain streams, but they tend to live in the quieter margins of these streams. When mature, the nymphs crawl out of the water and the adult emerges.

Nymph imitations can be useful when drifted along the edges of streams where they occur. Impart a little action with the rod tip to mimic the swimming behaviour of the nymphs. Undercut banks are especially good places to swim your fly.

Nymph imitations can also be productive when drifted or retrieved with short strips through the shallows after the naturals have migrated there. However, take particular care when fishing here because the quiet, shallow water makes trout spooky.

Because the duns emerge on land, they are not available to trout during a hatch. But a little wind can blow them onto the water, and since most of the action is on small streams the duns end up not far from trout; spinner imitations are seldom useful to anglers.

Overall, this is not a major western hatch. And on streams where it rates some attention, the nymphs are much more important than the duns and spinners.


How to Match a Ameletus

Hatches are matched from Westfly's database of "standard" fly patterns.

Size 10-14 Pheasant Tail. Brown, Olive
Size 10-14 Hairwing Dun, Comparadun, Sparkle Dun. Brown, Olive
Bankwater, backeddies: standard dry fly


NYMPH COLOR: Brown, with hints of purple or red

DUN SIZE: 10-14 mm (3/8-7/16 in)

DUN COLOR: Wings--mottled. Body--browns, olives

OTHER CHARACTERISTICS: Nymph--three fringed hairs; slender shape. Dun--two tails