Little Black Caddis

Telling it apart

• Tiny, size 18–20, entirely black body and wings.
• Wings held tent-like at rest — the trait that separates it from a midge at this size.
• Long, thread-like antennae, unlike a chironomid's short ones.
• A net-spinning larva that spins a finger-like silk tube, anchored in the fastest, cleanest rapids.
• Flies in dense swarms over fast water, often mistaken from a distance for a cloud of midges.

A finger-shaped net

The Little Black Caddis larva spins a fine silk tube, closed at one end and open to the current at the other — something like a glove finger anchored to a rock. Water passing through deposits organic particles that the larva harvests regularly.

That kind of net needs exceptionally clean, fast water to work well, which confines the larva to the swiftest, best-oxygenated riffles — often the most turbulent stretch of a river, where few other net-spinning insects bother to settle.

Tiny, so it's easy to misidentify

At this size, the first impression is almost always "midge" rather than "caddis" — an easy mistake from a distance, especially in a dense swarm over a riffle. Two details settle it fast: the wings, held tent-like on the caddis rather than flat as on a chironomid, and the antennae, long and thread-like rather than short.

It's worth checking, because the imitation for each insect looks nothing like the other.

Fishing water few other insects can handle

Because the larva demands exceptionally fast, clean water, its presence in a given stretch is a good sign of that water's quality. A small black nymph or pupa, fished near bottom in the fastest riffles, covers this species well even outside a hatch.

On the surface, a tiny black dry, nearly invisible to the eye in a riffle's white water, still gets spotted by trout — trust the zone rather than what you can actually see floating.