Midge / EmergersCDC Biot Caddis Emerger
The CDC Biot Caddis Emerger is a midge emerger pattern designed by Larry Medina. This effective pattern combines traditional materials with proven techniques for consistent results in a variety of water conditions.
Spring, Summer, Fall
Intermediate
Trout
Feb 2026
Overview
Larry Medina's CDC Biot Caddis Emerger uses goose biot for the body to create the segmented, translucent appearance of an emerging caddis. The CDC wing captures the half-emerged adult struggling at the surface, a vulnerable stage that trout target aggressively. This pattern sits low in the film where fish expect emerging caddis, with the CDC providing both flotation and realistic wing texture.
Materials
Hook: Medium or fine wire dry fly hook sizes
Thread: 8/0, black
Body: Peacock herl or dubbing
Wing: Painted Brown Swiss Straw
Hackle: Dark Brown hackle
Legs: Orange grizzly rubber
Behavior & Presentation
Natural Behavior: Ascending caddis pupae tumble upward through mid-column before hanging suspended in the film while adults extract from pupal shucks. This vulnerable film stage concentrates feeding activity.
Where Trout Eat It: Fish position in feeding lanes to intercept pupae suspended in the surface film and just below.
How to Fish It: Present with drag-free drifts in the film, allowing the fly to hang naturally without added weight.
Best Water: Target tail-outs, slicks, foam lines, and seams where emerging pupae accumulate during hatches.
Strike Type: Delicate sips barely dimpling the surface as fish confidently take suspended emergers.
Fishing Strategy
Rigging Suggestions: Use a 12-15 foot leader with 6X-7X tippet. Fish alone or as a dropper beneath a small dry fly.
Seasonal Timing: Most effective during peak feeding periods at dawn and dusk. Water temperatures between 45-65°F typically produce best results.
Pro Tips: The biot abdomen and CDC wing create the perfect emerger silhouette. Fish are often more selective to emergers than adults during caddis hatches.
Entomology
Caddis pupae ascend through the water column in an uncontrolled tumbling motion before reaching the surface where they hang suspended while the adult works free of the pupal shuck. This vulnerable transition phase concentrates fish feeding as insects struggle at the surface film unable to escape predation.
- Order
- Trichoptera
- Common Name
- Caddisfly
- Organism Type
- insect
- Life Stage
- general