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Hatches › Stonefly
Isoperla · genus
Small yellow stoneflies that bring trout up when adults skitter and nymphs drift in riffled current.
Category
Stonefly
Category
The insect or forage category for this profile.
Size
Generally small; commonly matched in the little yellow stonefly range, about hook sizes 14-18.
Size
Typical size range anglers imitate on the water.
Key stages
Eggs, Nymph, Mature Nymph, Emerger, Adult Stonefly, Egg Laying Female
Key stages
Life stages most relevant to fly fishing this hatch or forage.
Water types
freestone rivers, riffles, pocket water, medium streams, smaller rivers
Water types
Water types where this bug or forage is commonly found.
Yellow Sally is an angler name for small stoneflies in the genus Isoperla, a group of perlodid stoneflies in the order Plecoptera. In Idaho, anglers mainly match them as slim yellow stonefly nymphs and as fluttering adults seen along broken-water banks and riffles.
Also known as: Little Yellow Stonefly
Female stoneflies release their egg pods into the river, where they develop until hatching.
Young stonefly nymphs thrive among the river's rocks, feeding and growing through a series of molts.
As the nymph reaches full size, it begins to migrate towards the riverbank to prepare for its emergence into an adult.
During this transitional stage, the nymph crawls out of the water, and the adult form begins to emerge from its nymphal skin.
Adult stoneflies have a brief aerial existence focused on mating. Following reproduction, the cycle continues as tiny grubs hatch from the eggs and begin to feed on decaying organic matter.
After mating, the female stonefly deposits her egg pods into the river. These eggs will hatch into tiny grubs, starting the new generation by feeding on organic debris.
Nymph
Charlie's Fly Box
Materials
Mature Nymph
Ralph Long
Materials
Emerger
The Weekly Fly
Materials
Adult Stonefly
Fly Fish Food
Materials
Yellow Sally
One species, multiple rivers.
