If there’s one bug to have dialed through late spring and summer, it’s the caddis. These tent-winged insects are some of the most prolific and important food sources for trout—especially during the warmer months.
When to Fish Caddis
Caddis are present year-round in most bodies of water but hatches usually start to heat up in May—the Mother’s Day hatch on the Arkansas here in Colorado can be legendary—and can stretch into June or July, with some species like the October Caddis arriving in the fall. Late afternoons and evenings are prime time, especially when the water warms up.
Hatches tend to begin in downstream sections of water, moving upstream as the temperatures at higher elevations increase. If you find yourself back in a place where you’ve recently fished a good hatch or if a good hatch seems to be dying down late in the day try moving upstream.
How to Fish Caddis
Caddis spend most of their lives—up to a year—life in the larval stage. During this time they live on the bottom of the river, clinging to rocks. The classic “cased caddis” builds its protective cases out of gravel or plant debris, while other varieties are free-living, crawling rather than swimming while looking for food.
Metamorphosis transforms the caddis into a pupa—the transitional stage between the aquatic larva and the terrestrial adult. As they emerge, the trapped gases that help them rise to the surface make them appear sparkly or translucent—a trigger for fish.
When you’re seeing consistent topwater eats, switch to a dry like the Chimera or a more traditional Elk Hair Caddis and keep an emerger on as dropper to improve your odds. A slight twitch to imitate the caddisfly’s egg-laying movements can help entice an eat.
Putting It All Together
A good caddis hatch can feel a little chaotic. A cloud of bugs doesn’t always mean fish are eating adults. If they are flying high and fast toward the bank, they are freshly hatched adults headed to land to dry their wings. Fish probably aren’t feeding on these adults yet but are likely still eating the emergers that are yet to hatch and crippled adults struggling to leave the surface.
If they’re flying low over the water and dipping onto or skittering across the surface, they’re laying eggs and trout are almost certainly looking up.
When in doubt, tie on a dry fly imitation with an emerger as a dropper. Give the dry fly a twitching motion and let the flies swing parallel to the bank before recasting, allowing the dropper to rise through the water column like an emerging bug.
