Montana Fly Fishing Insects : Spotted Sedge

Net-spinning caddisflies (Hydropsyche cockerelli)

Abundant in many of the blue-ribbon trout rivers near Bozeman, Montana, the net-spinning caddisflies like moderate to fast-moving rivers because they are cold and highly oxygenated.

Named ‘net-spinning caddis’, these insects filter food by constructing a capture net that suspends in the current above their fixed retreats (like cocoons) made with plant and mineral fragments. They live on the tops submerged cobble, rocks, boulders, and logs to ensure their food source filters right to their ‘nets’.

https://stroudcenter.org/virtual-learning-resource/freshwater-rockstar-net-spinning-caddisfly/[KDA1]

Since hydropsychids have very specific standards of living, they are an indicator species of cold, clean water. When you find these insects around, you know the water is good and clean for trout.

Often called ‘spotted sedges’ by anglers, it is best to imitate the larval stage as that can be prolific and happen year-round but will start to emerge in the spring and go through fall. When the female lays her eggs on the water, which happens just before dark during warmer weather, the adult version can also induce a top-water eat from hungry trout.

These common caddis hatches bring excellent dry fly fishing in Montana on most rivers in the Big Sky state. Look for swarming clouds above bankside vegetation to anticipate the egg-laying flights at dusk on the upper Madison and Yellowstone rivers throughout the summer months.

Tie on an imitation in hook size #16-#18 in greens, tans, or browns to match this hatch.