If a mayfly is an appetizer, the stonefly is a steak dinner. Most stoneflies are substantially larger than mayflies and more appealing to eat, but they are also not nearly as abundant in most river systems.
My fly box is full of stonefly patterns like:
It’s important to understand some of the major differences between stoneflies and mayflies in order to be able to fish, and tie, these flies successfully.
While the anatomy of mayflies and stoneflies is similar, there are a few distinct differences to take note of. The tail of a stonefly is more noticeable than that of a mayfly and is split into two strands, not three.
The stonefly nymph also has two distinct wing cases and patterns should be tied to somewhat resemble this. The stonefly also has two prominent antennae, which are fun to incorporate into fly patterns but I’m not sure if it is necessary for catching fish.
Stonefly stages of life
In a river, stoneflies require clean, well oxygenated water to survive, which is why they live mostly in shallow, fast moving water.
Unlike mayflies, which have a lifespan of approximately two weeks, the stonefly can live in its nymph stage for up to three years before finally swimming or crawling its way to the rocky shoreline to hatch. Stoneflies also have what is called an incomplete metamorphosis, which means they go directly from their nymph stage to the adult stage.
From a fishing perspective, it is important to first determine if a river system contains stoneflies. If it is a popular river, there is likely an online fishing report that’ll give you information about types of bugs in the river.
Personally, I enjoy figuring as much of this information out on my own. Turning over rocks in a fast moving stretch of water will often uncover some of these giant bugs. You can also walk along a rocky shoreline and look for nymph casings. The casings are quite distinct and easy to spot.