How to Pick the Right Fly (Part 3): Caddisflies 101

This is the third post in our series on how to pick the right fly. To see all the posts in this series, click here. 

By Spencer Durrant

Caddisflies are the buffalo wings of fly fishing.

Allow me to explain.

Buffalo wings are one of the greatest foods on this planet, second only to pizza. Everyone loves wings. Some of us prefer them boneless, bone-in, spicy, or mild, but I have yet to meet a respectable person who turns their nose up at wings.

That’s exactly how trout treat caddisflies.

And just like your first trip to a wing joint, the endless flavors and styles of caddisflies can feel overwhelming. Do I get the spicy habanero? How hot is the mild sauce? Do I want to eat real wings like a caveman, or boneless wings like a civilized person? 

By the end of this post, you’ll have the knowledge you need to waltz into your nearest trout stream and offer up a steaming plate of perfectly sauced and tossed caddisflies.

What is a caddisfly?

Caddisflies are one of the most abundant aquatic insects on this planet. There are approximately 14,500 species of caddis throughout the world. That’s almost five times more caddis than the 3,000 species of mayflies that exist!

The truly successful anglers memorize every caddis species by heart – scientific names and all. True angling mastery is only achieved if Latin flows from your lips like the water in a river.

Okay, I’m kidding. In all seriousness, understanding caddisflies is dead simple. 

All you need to know about caddisflies is:

• What they look like
• Their life cycle
• Best patterns to imitate them

Caddisflies are simpler than mayflies or stoneflies, in my opinion. Where you need to recognize individual hatches of mayflies (like PMDs or BWOs), you’re really only looking for one type of caddis. They’ll be different sizes and colors depending on where and when you fish, but that’s as complex as identifying caddisflies gets.

So, stick with this post and you’ll be a caddisfly expert in no time.

Caddisfly Life Cycle

As I said earlier, the key to understanding caddisflies is understanding their life cycle.

Unlike mayflies and stoneflies, caddisflies have both a larval and pupal stage. In layman’s terms, that means there are two stages of caddis nymphs. With mayflies, for example, there’s only one nymph stage.

A caddis hatches from its egg and spends the first part of its life as a larvae. At this point, a caddis looks like a small worm with a heavily segmented body. Caddis are usually some interesting shade of green at this point in their life.

After the larval stage, caddis grow into a pupa. A pupal caddis builds a cocoon in which it lives until it’s ready to hatch as an adult.

Now, something important to note here: you’ve probably heard the phrase “cased caddis.” Caddis are pretty ingenious little bugs, and often build small cases out of rock and other river debris, in which they live as a larvae. Their cocoons look similar to these rock cases, too. A cased caddis pattern can be used to imitate both a larval or pupal caddisfly. Not all caddis larvae live in cases, however. Some are “free-swimming”

So, back to the life cycle – once caddis are ready to hatch, they emerge quickly to the surface where they escape the water as quickly as possible. Unlike mayflies, caddisflies spend as little time as possible on the water. In fact, adult caddisflies almost never willingly drift along the water’s surface until it’s time to mate. If you see an adult caddis drifting on the water’s surface, it’s probably a crippled adult.

Adult caddisflies are easy to spot – they look almost like moths. They have long, tent-like wings that fold against their body, which is usually slightly tapered and comes in a variety of colors. Caddisflies have long antennae facing forward off their head, and fly with a fluttering motion.

Caddis hatch from late spring (usually around Mother’s Day) through fall. Some of the biggest hatches occur an hour or so before sunset, especially during summer.

Identifying Hatch Sages

The stages of a caddis hatch are very similar to that of a mayfly hatch. Caddis emerge from their pupal cocoons to become adults (duns), then return to the water to lay their eggs. As the hatch moves along, the trout key in on eating bugs at that certain stage of the hatch.

What you need to pay attention to is how the fish are rising to eat off the surface. Trout create unique patterns when they rise to eat bugs – we call these rise forms. The rise form tells you whether the trout are eating emergers and cripples, or duns.

Emerger Rises

Trout eating emergers create a unique rise form. Instead of seeing a fish’s head when it eats, you only see the back and tail fin. This happens because fish are eating bugs as they travel to the surface or are stuck in the surface film – emergers and cripples.

A crippled caddis is exactly what it sounds like. It’s either a dun or emerger that has some sort of crippling deformity that prevents it from leaving the water’s surface.

Dun Rises

When trout eat duns, they create the classic dry fly rise form. Their head breaks the surface, leaving behind the “ring of the rise” we’re so familiar with.

Something else to note here: there’s a specific caddis pattern called the “egg laying caddis.” It’s a fly meant to imitate female caddis as they return to the water to lay their eggs. Trout will often eat them with the same dun rise they eat other adults.

Matching the Caddis Hatch

Now that we know what caddisflies are, their life cycle, and the rise forms trout create when eating caddis off the surface, we’re ready to dive into matching a caddis hatch.

Really, matching just about any caddis hatch boils down to the following:

• Match the size of the caddis on the water/in the air
• Match the color of the caddis on the water/in the air
• Match the hatch stage if trout are keyed in on something

As with any hatch, you want to match the size of your fake bug to the real ones on the water. Size is the most important factor to consider when choosing a fly to imitate a real aquatic insect. Most caddis fall between a size 14 and 18. You’ll rarely need anything outside of that range.

Caddis hatch with a wide variety of colors. From light tan to dark gray, you need to have a lot of colors of caddis in your box. Some fish, especially on heavily-pressured rivers like tailwaters, will get picky about the color of the caddis.

The only caddis that sort of breaks this mold is the October Caddis. This bug is huge, has a bright orange body, and hatches in late fall – often in October. The October Caddis is usually the last big bug to hatch on any given trout river.

Finally, you may find some trout that really only want an emerging or crippled caddis, instead of the adult. Trout tend to care a bit less about this than they do with mayflies, but it’s still a good idea to have a solid collection of emerging, crippled, and adult caddis patterns in your box.

Speaking of patterns – these are the ones you absolutely need while on the water:

• Elk Hair Caddis – the GOAT of caddisflies
• Mop Fly – a fantastic free-swimming caddis nymph imitation
• Olive Caddis Larvae – a must-have if fish are eating caddis nymphs
• Flashback Pheasant Tail – can be used to imitate a cased caddis if needed
• Parachute Caddis – great for imitating egg-laying or emerging caddisflies

Hit the Water

If you feel like you just walked out of an all-you-can-eat wing joint, join the club. That was a TON of information we just covered.

Thankfully, caddisflies are pretty simple – just like buffalo wings. They all share the same size and shape, differing really only in color. Learn to recognize what a caddis looks like, and how trout rise to eat them, and you’ll be in business.

The next post in this series will focus on everyone’s favorite little fly – the midge. Until then, go hit the water and let us know if you catch anything!

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