Brown and rainbow trout arrived in Chile in the early 1900s, carried in on the same wave of introductions that stocked New Zealand and Argentina. Then, in most of Patagonia, nobody touched them again.
That is the single fact that shapes the fishing here. Nothing is stocked. Every trout in the Ñirehuao, the Simpson or the Paloma was born in that water and has eaten nothing but what the river produced. It makes them harder in a specific way: a hatchery fish forgives a dragging fly, and a wild one does not.
Brown trout: the technical one
The fish most people come for. Browns hold in the difficult places — under cut banks, tight to structure, in the seam nobody wants to wade to — and they are unforgiving about presentation. On a spring creek they will watch a fly drift past four times and take the fifth only if nothing about it looked wrong.
They peak twice in our season. First in the dry fly window of January and February, when hoppers and beetles fall off the banks and the takes happen on the surface where you can see them. Then again in March and April, when the pre-spawn migration pushes the biggest fish of the year up into water where you can reach them, and articulated streamers on sinking lines start to make sense.
Rainbow trout: the early season fish
Faster, more acrobatic and considerably less cautious. Rainbows fish hardest at the opening of the season, from October into mid November, when the water is high with snowmelt and they sit tight against the banks and structure waiting for whatever the current brings.
This is the streamer window. Heavy baitfish patterns on 200 to 250 grain sinking lines, worked close to the bank on freestone rivers. It is less delicate than the dry fly season and, for a lot of anglers, more fun.
What size to actually expect
A normal day produces fish between 18 and 24 inches. That is a high average by most standards, and it is the number we would give you on the phone.
Bigger fish exist. The autumn migration is when they are most reachable, and every season produces a handful that people talk about for years. But an operation that puts a specific number in its marketing is making a promise the river has not agreed to.
Everything is released
A wild population that has sustained itself for a century does so because nobody takes much out of it. We fish barbless where the water calls for it, keep fish wet, and release everything. The Sernapesca licence that comes with the trip sets the legal framework; the practice on the boat goes further than the law asks.
If you want the month-by-month version of this — hatches, water levels and which technique fits when — that is on the fishing season page. For the wider picture of the country, see fly fishing in Chile.