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Fly Fishing 101, Part 14
Underwater Caddis


Last time we talked about the caddis you can see. Those that are flying around or floating on the surface of the water. Trout love them! They may be the most prevelent insect trout eat. But the ones you see are only a small portion of the ones trout eat!

How can that be? Remember a while back I said you don't have to be an expert on insects to catch fish? I didn't lie, but some basic knowledge will help a lot. Caddis, unlike some of the insects we will talk about later, are found in primarily two forms (growth stages) that trout eat. The first, the adult where they are flying and floating (which we discussed last week) and the underwater stage where the caddis exists before becoming an adult.

There are tons of different caddis. So many that several books have been written on just them caddis. In the previous column I recommended one of the latest, Richards and Braendel's, Caddis Super Hatchesfor detailed information. Another is Caddisflies by Gary LaFontaine.

Basically, caddis begin as eggs. The tiny larva comes out of the egg and constructs a case around itself for protection. This case can be tiny bits of bark, small pebbles, sand or leaf fragments. As it grows it enlarges the case. In about a year the larva encases itself in a cocoon of silk and seals itself in. While in the cocoon the caddis develops legs and wings. When it is ready to emerge it bites out the end of the cocoon, swims to the surface, dries it wings and flies away. The caddis mate, the female lays her eggs and the cycle begins again.

Trout have opportunities to feed on the caddis all through this cycle. However, studies absolutely prove trout eat 90% of their diet underwater. By careful observation you can tell if the trout are feeding beneath the surface.

If trout are not rising that is taking some insect from the surface watch for "bulging." Often trout take the insect just below the surface, and turn their bodies as they do; resulting in a "bulge" on the surface. This is often mistaken as a rise by novice fly fishers.

Caddis Pupa
Caddis drawing from Presentation by Gary A. Borger
Drawings by Jason Borger
Published by Tomarrow River Press

Another thing to watch for is a "flash." Watching the water you may see a flash of the trout's sides. That flash is a sure indication the trout is feeding subsurface as the caddis swims towards the surface, or as the insect scurries across the bottom. These two examples are probably the caddis trout most often eat.

There are varying opinions on the proper method to fish nymphs. Technically caddis are not nymphs, but the common name for underwater insects, and the method of fishing the imitations has become known as nymphing. One of the most effective, at least for caddis, is to cast your fly line, using a rather long "greased" leader. The "greased leader" is simply a normal leader which has a coating of fly floatant down to about 4 inches of the fly. The nymph (or weighted nymph) sinks without the leader being visable.

While current nymphing methods call for casting the line across the current and letting it travel downstream, this may not be the most effective method.

Remember the fish are facing into the current or upstream. Your chances of hooking a fish directly downstream are not the best. A better tactic is to cast upstream, again with the floating line and greased leader. This puts the fly at the proper eye level for the trout and will help insure hooking the fish.

It is important to match the size of your fly to the size of the real insect. Generally commercial nymph patterns are too large. If you have a choice in nymph patterns, use the smaller not the larger.

Look for another tied imitation for caddis just before they are ready to hatch. These are called emerger patterns. Quite often emerger patterns are constructed using hackle not intended to float, also called soft hackle flies. Others have trailing pieces of mylar or other materials tied at the rear to represent the shucks.

If your casting is not perfect, or nymphs are not your view of fly fishing is about, be sure to check out the Fly of the Week Archives for other very productive dry fly caddis imitations. Next: Stone flies.

Stop by the Chat Room and meet some fellow anglers. It is a nice bunch of people - always willing to lend a hand! Or just share your fishing adventures. Fair skys and tight lines, ~ DB

Have a question? Email me!

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