Stonefly
Also called Stonefly nymph, Plecoptera
Stoneflies 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.
- Group
- Aquatic insects
- Category
- Entomology & forage
- Level
- Beginner
- Water
- Freshwater
Last updated
What Stonefly means
Flip a stream rock and you will often find stonefly nymphs clinging tight. They are flattened insects that mostly live in moving water and need good oxygen.
Many stoneflies emerge by crawling to the bank or onto rocks and wood, then splitting their shuck and walking away as adults. That behavior is why adult stoneflies show up along shorelines, boulders, and overhanging brush.
On the water, stonefly imitations show up two main ways. A weighted stonefly nymph is a common anchor fly in a nymph rig. Adult patterns get used tight to banks, along grass edges, and around structure when adults are active or getting blown onto the water.
Why it matters on the water
Stoneflies help you pick water. If a river supports healthy stonefly populations, it usually has the kind of cold, well-oxygenated flow that also holds trout, and it often has bank structure where adults collect. That points you toward riffles, pocket water, and edges with rocks and wood.
Stoneflies also help you choose fly size and profile without overthinking exact species. Big stonefly nymphs and adults call for bigger hooks and heavier flies than most mayflies and midges, and they justify fishing close to the bank instead of only targeting mid-channel seams.
Read next
- CaddisflyA caddisfly is a common freshwater insect that trout and other fish eat in its larva, pupa, and adult stages. Many species live in streams and rivers, and their hatches can drive steady feeding.
- 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.
- SalmonflyA 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.