Corixa (water boatman)

Corixa is one of the more overlooked flies in put and take, but in the right place and at the right time it can be genuinely effective. It imitates a water boatman, a small aquatic insect that lives in shallow water and swims in quick, diving darts. When rainbow trout are holding shallow near vegetation and you cannot see what they are eating, a Corixa is often worth a try.

An insect with a particular way of moving

Water boatmen (Corixa) are small, sturdy aquatic insects that live among vegetation in the shallows. What is special is how they move: they swim in short, sharp bursts and dive toward the bottom, often to fetch air which they carry as a small silver bubble. That diving, jerky movement is what you want to recreate, and it is also what sets the Corixa apart from calmer imitations such as nymphs and pupae. Many patterns have a shiny belly that hints at the air bubble.

When it comes into its own

The Corixa is a distinctly shallow-water fly. It works best near reeds and vegetation in the shallows, especially in late summer and autumn when the water boatmen are at their most active. It is a smart choice when you see rainbow trout feeding shallow without being able to tell what they are taking, or when you want to try something other than the usual nymphs on that kind of water. On small waters with plenty of plant growth it often comes into its own.

How you fish it

Fish the Corixa in shallow water with short, quick strips that imitate the water boatman’s diving swim, and let it sink a little between strips. A lightly weighted version helps the fly dive and gives it the right movement. Aim your casts at reed edges and gaps in the vegetation, and vary the strips until you find the rhythm. The key is the movement, not the exact pattern, so do not be afraid to fish it a bit lively.

A specialist worth having

Corixa is not an all-round fly, but in shallow water with the right conditions it can outfish more classic patterns. Treat it as a specialist for shallow fishing, alongside your nymphs. The basics of presentation it shares with nymph fishing, and more patterns to switch between are in flies for rainbow trout.