Grannom

Other Common Names: Mothers Day caddis, black caddis
Scientific Name: genus Brachycentrus

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."

Characteristics

LARVA COLOR: Cream or green body

PUPA SIZE: 6-12 mm

PUPA COLOR: Body--Green body. Shroud--Tan

ADULT SIZE: 6-12 mm

ADULT COLOR: Wings--brown or black. Body--Green or dark brown.

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.

 

Click on the fly name to see the pattern. Click on the presentation to learn how to do it.

STAGE PATTERN SIZE/
COLOR
PRESENTATION WHERE
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
Soft Hackle 12-16
Green
surface swing, shallow nymph Riffles, moderate-fast runs; just below these
Adult Elk Hair Caddis 12-16
Body: green, dark brown; Wing: brown, black
standard dry fly Bankwater near foilage
Parachute Caddis 12-16
Body: green, dark brown; Wing: brown, black
standard dry fly Bankwater near foilage
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 12-16
Body: brown; Wing: black
surface swing, shallow nymph, rising nymph Riffles, current seams, backeddies below riffles
Diving Caddis 12-16
Body: brown; Wing: black
surface swing, shallow nymph, rising nymph Riffles, current seams, backeddies below riffles