The short answer
- Mayflies: the Pheasant Tail and the beadhead Hare's Ear, sizes 10 to 18; an Aysén guide fishes the Pheasant Tail in 14 and 16.
- Stoneflies: heavy long-shank nymphs, mostly sizes 6 to 10, drifted along the bottom of the riffles.
- Caddis: a beadhead larva in sizes 8 to 16 on the bottom, and a Soft Hackle or Sparkle Pupa when trout chase the hatch.
- Lakes: damsel nymphs along the weed beds, and dragonfly nymphs such as the San Dragon fished deep with short strips.
- With no fish rising, a nymph is the default: aquatic insects spend most of their lives underwater.
- Flies are included in both of our programs: bring your own only if you enjoy fishing them.
The Coyhaique nymph box at a glance
Eight stages cover the subsurface fishing around Coyhaique, from the riffles of the rivers to the weed beds of the lakes. The sizes are ranges: the naturals under the rocks decide the exact fly on the day.
| Imitates | Patterns | Hook size | Depth | Water |
|---|---|---|---|---|
| Mayfly nymphs, swimming or rising | Pheasant Tail | #14–16 | Mid-water to just under the surface | Rivers |
| Mayfly nymphs on the bottom | Beadhead Hare's Ear | #10–18 | On the bottom | Rivers |
| Mayfly emergers | Flymph | #12–18 | Just under the surface film | Rivers |
| Stonefly nymphs | Charly Stone, Kaufmann Stone | #6–10, long shank | On the bottom of the riffles | Rivers |
| Caddis larvae | Beadhead Caddis Larva | #8–16 | On the bottom | Rivers |
| Caddis pupae | Soft Hackle, Sparkle Caddis Pupa | #12–16 | Rising; swung through the tail of a pool | Rivers and lakes |
| Damselfly nymphs | Whitlock Damsel, Marabou Damsel | #10–14 | Along weed beds and the shore | Lakes |
| Dragonfly nymphs | San Dragon, Dragon Andino | #6–10 | Deep, with short strips | Lakes |
Patterns and sizes follow a Chilean aquatic entomology guide for fly anglers (Sandoval, Ríos y Senderos, 2001–2003), written for all of Chile rather than for Aysén. The Pheasant Tail sizes come from an Aysén guide's hatch chart (Heinonen, Kalakamu), emergers and pupae are sized to the adults on that chart, and damsel and dragon sizes are our own lake notes. Ranges, not rules.
How deep should a nymph fish?
Most of an aquatic insect's life is spent underwater: a year for small stoneflies, two to four for the big ones, up to three for some dragonfly nymphs. That is why depth matters more than pattern. Stonefly nymphs and caddis larvae live on the bottom, so the fly has to tick along it in a completely free drift. With that much weight, keep the rod high: less line in the current and a direct feel for the take.
Mayfly nymphs split by habit. Crawlers and clingers stay on the stones; swimmers and rising nymphs move up through the water. Cast upstream and slightly across, start where a riffle spills into a run or a pool, and let the fly drift as far as it will. Repeating the same drift is not wasted time.
In the lakes, damsel nymphs work the weed beds and the shore, and dragonfly nymphs are fished deeper with short, sharp strips. Rods and lines for the trip are in our packing list.
| Rod | 5- or 6-weight |
|---|---|
| Line | Floating; sink-tip for heavy stoneflies |
| Leader | About 13 ft (4 m), tapered to 5X |
| Deeper runs | Add a length of 5X or 6X tippet |
| Weight | Beadhead or non-toxic split shot |
A starting point from the Chilean entomology guide: your fishing guide adjusts it to the water on the day.
Which nymph for which insect?
Each insect has its own field note with the science behind it. This is the short version, from the riffles to the lakes.
Stoneflies: Charly Stone and Kaufmann Stone
Sizes 6–10, long shank · rivers
January riffle samples found Limnoperla jaffueli at up to 630 nymphs per square meter in the Mañihuales, and Klapopteryx kuscheli spends more than two years as a nymph, so stonefly nymphs are trout food all season. When they hatch, most crawl out onto the bank, which pulls trout toward the edges. An Aysén guide rates big rubber-leg stonefly nymphs as productive all season.
Caddis: Beadhead larva, Soft Hackle and Sparkle Pupa
Sizes 8–16 · rivers and lakes
In the Palena River study, caddis were 21% of the prey items of adult brown trout, second only to snails. Free-living and net-spinning larvae look alike to a trout, so one beadhead larva covers both, and color matters least. For cased caddis, a palmered hackle trimmed short suggests the twigs of the case.
Mayflies: Pheasant Tail and Hare's Ear
Sizes 10–18 · rivers
A January survey counted up to 643 mayfly nymphs per square meter in the rivers we fish. Crawlers and clingers hold to the stones, so fish a weighted Hare's Ear. Swimmers drift and swim most at the start and end of the day, and rising nymphs head for the surface: there, an unweighted Pheasant Tail.
Damselflies: Whitlock Damsel and Marabou Damsel
Sizes 10–14 · naturals ⅝–1¼ in · lakes
Damsel nymphs are slim, with three tail gills. In late spring and early summer they migrate toward shore to hatch, the best moment to fish them. Patterns are tied mostly in olive and brown, with big eyes and a fibrous tail that suggests the gills.
Dragonflies: San Dragon and Dragon Andino
Sizes 6–10 · naturals 1–1½ in · lakes
Bulkier, with no tails, and some live up to three years as nymphs, so they are in the lakes all season; adults emerge from October to March with no single peak. Fish them deep with short, sharp strips that copy their jet-propelled swimming. The San Dragon, a Rodrigo Sandoval pattern, is the dragonfly nymph the Chilean entomology guide rates most consistent in southern waters (its author tied it); the Dragon Andino is Carlos Correa's.
Snails and crabs: Dark, weighted flies
Slow, on the bottom · rivers and lakes
Not insects, but a big share of what trout here eat. Snails were the top prey item of adult brown trout in the Palena River, and in a 1972 study of Chilean river trout, pancora crabs made up about two-thirds of the dry weight of their stomach contents. Dark, weighted patterns fished slowly along the bottom cover both.
Nymph or dry fly?
With no fish rising, start with a nymph. When trout start showing, the rise itself tells you whether they are eating under the surface or on top: a dorsal fin breaking the film means emergers, not duns. Our guide on how to read a trout rise walks through each case.
On slow days, an Aysén guide's go-to is a dry-dropper: a big Stimulator or Fat Albert with a beadhead Pheasant Tail or a Perdigon hanging under it. And in October, when big rainbows hold in clear water, the nymph becomes a sight-fishing game, as our spring sight-nymphing guide explains.
Do you need to bring your own nymphs?
No. Flies are included in both of our programs, and the all-inclusive expedition includes tying materials as well. If you enjoy fishing your own patterns, bring them. The flies for the surface are in our dry-fly guide.
