The life of a stonefly is much simpler when compared to the other bug types we've covered.

Their life cycle progresses from Nymph → Adult


Stonefly nymphs look pretty similar to mayfly nymphs, but much larger. They are usually found clinging to the underside of rocks in highly-oxygenated water (riffles). Once nymphs are grown, they climb out of the water (onto stream-side rocks or logs) and hatch into adults. If the stonefly population on a given stream or river is prominent, you'll often find left-behind casings near the bank. Watch for them (see picture below)!


Stonefly adults don't move too far from where they hatched. On windy days, they can get blown into the water and gobbled up by opportunistic trout. After a few weeks, swarms of adult stoneflies will mate, lay their eggs, then die.


How do I recognize a stonefly?

1. Most of them are BIG❗️ We're talking 1-3 inches long (see pictures below).

2. Large flat folded wings on top of their body ✅⁣


Now let's talk fly imitation:

Size & Color

Did we mention they're big? 😜 Most range from size 6 to 12. They vary in color (black, brown, tan, and even yellow). If you find a stonefly, try your best to match it to a fly in your box. We would argue that getting the size right is more important than the color.  


Sub-surface or dry fly? Examine your surroundings to make that decision.

If you turn over a couple of rocks and find some stonefly nymphs, try a nymph rig.

If you have an adult stonefly land on your shoulder or you see a lot of casings around.. try chucking a dry fly. You may even consider a dry-dropper rig. Dry stonefly imitations are big enough that they will pretty easily stay afloat with a large nymph pattern attached.  

Check out some of our favorite imitations below.


We hope you found this helpful. If you have any specific follow up questions feel free to ask them through our "Contact Us" page. We are always happy to help.

Click below to check the BONUS section—Streamers!