Grannom

LARVA SIZE: 12-17 mm, including case

LARVA COLOR: Cream or green body

PUPA SIZE: 6-12 mm

PUPA COLOR: Green body, tan shroud

ADULT SIZE: 6-12 mm

ADULT COLOR: Green or dark brown body, brown or black wing

OTHER CHARACTERISTICS: Larva live in square case made from plant material. Body, wing, and shroud colors can vary, so it's always best to check a natural insect where you are fishing. Body and wing colors will darken when the insect is ready to lay eggs.

Mouse-over for alternate views: Larva 1    Larva 2    Adults

About Grannoms

Grannoms build square-shaped cases and live in riffly water or runs with moderate to fast currents. Larvae are sometimes knocked loose, so a cased caddis pattern dead-drifted near the bottom might pick up some fish.

Pupation occurs in the same water that the larvae lived in. During a hatch, dead-drift a pupa pattern near the bottom in riffly water or just below riffles. An unweighted pupa pattern can also be drifted near the surface, or you can present a Soft Hackle with wet-fly swing. Another good strategy is a dry fly with a pupa pattern as a dropper or trailer; the dry fly acts as an indicator and sometimes is taken by the trout.

After the hatch, errant and unlucky adults fall onto the water, and a dry fly is the right choice. Bankwater downwind or downstream from overhanging trees is a good place to cast your dry.

Female grannoms swim or crawl underwater to lay eggs. You can fish a dry at this time, or go subsurface with a Soft Hackle or Diving Caddis pattern.

Grannoms hatch in spring and fall. The fall adults are smaller and are usually black, hence their nickname, "black caddis."

Articles About Grannoms

Click headline to read entire article

Grannoms Grannoms are an important caddis family that is common in Western waters. They are especially important in spring and fall. But what do they have to do with your mother? by Rick Hafele and Dave Hughes

Caddis Larvae--Part I Imitations of caddis adults and pupae are staples of a well-stocked Western fly box, but larva imitations are generaly absent. And the rare angler that carries larva patterns usually has the wrong ones. by Jeff Morgan

STAGE

PATTERN

SIZE/
COLOR

PRESENTATION

WHERE

Larva

Cased Caddis, Brachycentrus Larva

10-16/Body: cream, green; Case: brown

Indicator, Tight line

Riffles, moderate-fast runs; just below these

Pupa

Deep Sparkle Pupa

12-16/Body: green; Shroud: tan

Indicator, Tight line

Riffles, moderate-fast runs; just below these

Sparkle Pupa

12-16/Body: green; Shroud: tan

Indicator, Tight line, Shallow nymph

Riffles, moderate-fast runs; just below these

Z Wing Caddis

12-16/Green

Indicator, Tight line, Shallow nymph

Riffles, moderate-fast runs; just below these

Soft Hackle

12-16/Green

Surface swing, Shallow nymph

Riffles, moderate-fast runs; just below these

Adult

Elk Hair Caddis, X Caddis

12-16/Body: green, dark brown; Wing: brown, black

Standard dry fly

Bankwater near foilage

Goddard Caddis

12-16/Natural gray

Standard dry fly, Skating

Riffles

Egg-layer

Soft Hackle, Diving Caddis

12-16/Body: brown; Wing: black

Surface swing, Shallow nymph, Rising nymph

Riffles, current seams, backeddies below riffles