American Grannom

Overview: The American Grannom Caddis (Brachycentrus americanus) is a species of caddisfly known for its unique hatching pattern, which makes it an important target for anglers during spring and early summer. This caddisfly is most commonly found in cold, fast-moving rivers and streams across North America. The American Grannom is a medium-sized caddis, easily recognized by its dark brown or olive body and distinctive dark wings, often with a grayish tint. The hatches of this caddisfly are important because they typically occur when the water temperature reaches the low 50s to mid-60s Fahrenheit, making them a key food source for fish during these transitional months. Common hook sizes for imitating the American Grannom Caddis typically range from 12 to 16.

Nymph Stage: The American Grannom Caddis nymph is small to medium in size, measuring about 0.75 to 1 inch in length. The nymphs are typically olive or brown in color, with a robust, segmented body and a darker thorax. These nymphs are bottom-dwellers, clinging to rocks and submerged vegetation in fast-moving streams, where they feed on detritus and small invertebrates. The nymphs are known to be active crawlers, migrating to shallower waters before emergence. Fly patterns tied on hooks sized 12 to 16 effectively replicate the size and appearance of the American Grannom nymphs. Dead-drifted presentations near riverbed structure, such as rocks and logs, are effective for enticing strikes.

Dry/Dun/Spinner Stage: The adult American Grannom Caddis, or dun, measures approximately 0.5 to 0.75 inches in length. It features a dark brown or olive body with large, translucent wings that often appear grayish. The American Grannom is most active during its hatch, which occurs in the late afternoon or evening, though it can sometimes emerge in the early morning hours as well. The adults are often seen fluttering on the water’s surface or perched on nearby vegetation. During the hatch, trout eagerly rise to feed on these insects, making it an exciting topwater fishing opportunity. Dry fly patterns for the American Grannom typically range from hook sizes 12 to 16