Salmonfly
Also called Pteronarcys, Pteronarcys californica, Giant stonefly
A salmonfly is a very large stonefly, best known for its late-spring to early-summer adult hatch on many Western rivers and the oversized dry flies it inspires.
- Group
- Stonefly & caddis hatches
- Category
- Entomology & forage
- Level
- Beginner
- Water
- Freshwater
Last updated
What Salmonfly means
Big, clumsy stoneflies crawling on streamside rocks are often salmonflies. The name usually points to Pteronarcys stoneflies, especially Pteronarcys californica, a dark, heavy-bodied insect that gets anglers’ attention because of its size.
Trout eat salmonflies in two main forms. Before the hatch, fish key on the nymphs, which live under rocks for a long time and get dislodged in higher flows. During the hatch, nymphs crawl out on bankside rocks and vegetation to emerge, then the adults flutter and fall back to the surface, especially along cutbanks, willows, and slower edges.
Fly patterns called “salmonflies” are big dries and big nymphs meant to suggest that profile, not a precise match. On many rivers they get fished tight to the bank, sometimes as the top fly in a dry-dropper with a stonefly nymph below.
Why it matters on the water
Salmonfly time pulls trout out of mid-river lanes and into the edges. If you focus on banks, inside seams, and soft pockets next to fast water, you cover the water where fish slide over to hunt big calories.
It is one of the few hatches where fly size and profile can matter more than delicacy. That changes leader and tippet choices, casting, and hook-setting rhythm, especially when you are throwing a bulky dry or pairing it with a heavier nymph.
Read next
- Dry flyA dry fly is a floating fly meant to be fished on the surface, where you can see it and the take.
- Golden stoneA “golden stone” is a common name for medium-to-large yellow to golden stoneflies, and the hatch anglers watch for when those adults are on the banks and fluttering on the surface.
- NymphA nymph is a subsurface fly meant to imitate an aquatic insect in its immature stage, or a small food item drifting in the current. Nymphs are fished with or without weight, an indicator, or tight-line methods.
- StoneflyStoneflies are aquatic insects whose young live mostly in moving water and whose nymphs crawl out to emerge. They are an important trout food, especially where big species like salmonflies and golden stones are present.