CDC Caddis

A dry fly, tied #14–20, carried year round. It is tied against 4 named insects in this book — April–August.

A dry fly that sits lower in the film than an elk-hair wing allows, built on a standard dry-fly hook in sizes 14–20 with tan 8/0 thread. The body is fine tan, olive or black dubbing; the wing is two or three CDC feathers set tent-style over it; the hackle is either absent or a sparse CDC collar. That construction is the whole point of the CDC Caddis — a soft, translucent wing that rides in the surface rather than on top of it, for flat water and educated fish where an elk-hair wing is too much fly. It is fished dry-fly-dressed and shaken out rather than false-cast, since CDC drowns under repeated casting. Tied against the Grannom, Brachycentrus spp., in April–May at 48–58°F; the Little Black Caddis, Chimarra atterima, in April–May at 46–58°F; and the Spotted or Tan Caddis, Hydropsyche spp., May–August at 55–70°F, as well as caddis generally. The target is trout, and it is carried all season.

#14–20Hook size
dry flyType
AllSeason
4Hatches matched

What it looks like

A drawing, not a photograph, and not traced from one. Its proportions were read off 5 independent reference photographs of the pattern and written down as 5 measured characteristics — wing angle, tail length against the shank, how far a hackle fibre reaches — every one of which had to hold across more than one of them before it could be drawn. What survives across many photographs of a fly is the fly.

The caddis tent again, but in CDC rather than elk. It sits lower and looks softer, which is what a fish on flat water wants and what an Elk Hair Caddis cannot do. Drawn at #18 — 6.0 mm of shank and 3.0 mm of gape on a Tiemco 100.

The bare hook at every size this pattern is tied in, all to the same scale. There is no industry standard behind a hook number, so these are Tiemco 100 measurements and another maker's 14 will differ a little.

What it imitates

Each of these is the same hatch record the app's own panel reads, so a pattern recommended on a river card in the app is recommended for one of the insects below.

It is also tagged for caddis generally.

Tying recipe

In tying order. This dressing is the standard one — these patterns have been in the publicrecord for decades — and materials substitute freely: the proportions and the silhouette are the pattern, not the brand of dubbing.

Hook	Standard dry-fly hook, sizes 14–20
Thread	Tan 8/0
Body	Fine tan, olive or black dubbing
Wing	Two or three CDC feathers, tent-style over the body
Hackle	None, or a sparse CDC collar

When to fish it

Flat water and educated fish, where an elk-hair wing is too much fly. Fish it dry-fly-dressed and shake it out rather than false-casting.

Carried all year. The insects it matches are active april–august, in water from 46°F to 74°F.

Target species

Trout

Rivers it fishes well

Rivers with a page here that sit in the regions where the insects this pattern imitates are recorded. It is a claim about coverage, not a report of a fish caught.

Related patterns

Same type of fly, or tied for the same insects.

Open the trout map →Every trout stream near you, coloured by today's water temperature.