Stoneflies have an incomplete life cycle and go from the Larva stage to the Adult stage. They can however stay in the Larva stage for up to 3 years, going through as many as 25 moults. The Stonefly Larva lives on the bottom of rivers and streams and sometimes among the rocks in lakes.
Although most Stonefly Nymphs are vegetarian, and live on the algae and vegetation of the stream bottom, some species are carnivorous.
These Stonefly species live mostly on mayfly and other insect larva.
Stonefly Nymphs are poor swimmers, preferring to crawl along the stream bottom or up on rocks and vegetation.
When they lose their grip they quite often become a handy snack for nearby trout.
A lot of fishermen have found that there is a relationship between Steelhead and the Stonefly. If you find hatches of Stoneflies when the Steelhead are running you will quite likely find Steelhead.
Some of the Stone Fly Nymph Fly Patterns include;
| Anderson’s Brown Stone | Bird’s Stone Nymph |
| Bitch Creek | Box Canyon Stone |
| Brook’s Stone | Brown Stone |
| Carriers Stone | Dark Stone |
| Dionne’s Stone | Early Brown Stone |
| Early Stone | Golden Stone Nymph |
| Kaufmann’s Black Stone | Kaufmann’s Brown Stone |
| Kaufmans Golden Stone | Large Black Stone |
| Little Yellow Stone | Matt’s Fur |
| Montana Stone | Morristone |
| Peacock Matt’s Fur | Pheasant Back Stone |
| Rubber Legs Brown Stone | Rubber Legs Hare’s Ear |
| Rubber Legs Kaufmann’s Stone | Stonefly Creeper |
| Ted’s Stone | Whit’s Black Stone Nymph |
| Whit’s Golden Stone Nymph | Yellow Stone Nymph |