The fish of one Patagonian river, on the record: wild browns, rainbows, brook trout and landlocked salmon on the Carrileufú, where they sit and what they eat.
Almost everything written about Patagonia trout treats Patagonia as one place: thousands of kilometers of water, browns and rainbows and brooks, superlatives all the way down. This is the opposite kind of page. It is about the fish of one river system, the Carrileufú and the lakes it connects, written by the lodge that fishes it every week of the season. Region-level truths are cheap; river-level ones have to be lived next to.
Fish this river
Tell us the month you have in mind and how many anglers, and we will send back what is open and what a week here includes.
How trout got into this water at all
There were no trout in Patagonia until the early 1900s. The native fish were small: puyen, silverside, Creole perch. Salmonid eggs began arriving in 1904 under an Argentine government program, shipped from the United States to a new hatchery near Nahuel Huapi, and rainbow trout from that era's shipments took hold almost immediately. Brown trout arrived by a different route, with eggs of European stock brought in from Chile around 1930. Within a few decades the rivers draining the Andes held wild, self-sustaining populations, and that is what swims here now: nothing in this valley is stocked, and the fish you catch descend from populations more than a century old.
Four species, one lake-and-river system
The Carrileufú is the thread of a larger system: it connects lakes, and the Rivadavia and Arrayanes carry the same water on. That geography is the single most useful thing to understand about the fish here. The lakes act as reservoirs, keeping flows and temperatures stable through the season, and they act as the deep home water the big fish move out of and back into. Four species live in it: brown trout, rainbow trout, brook trout, and landlocked salmon.
Average fish, honest numbers
Our head guide Diego has spent his working life on this water, so the numbers here are his, not a brochure's. Browns and rainbows in the waters around Cholila run 12 to 21 inches, with the average fish sitting at 16 to 17 inches and occasional fish at 22 and above, mostly browns. The biggest fish of last season was a 23-inch brown, and there are bigger ones in the system. The brook trout run smaller, around 14 inches, and the landlocked salmon 16 to 20, both in much lower numbers than the trout. No 30-inch marketing here; those are the honest figures, and a 16-inch wild fish in water this clear, eating a dry fly you watched it rise to, is the whole point of the trip.
Brown trout: the resident and the traveler
The browns are why anglers cross an ocean for this valley. Diego's read on where they live: tight to the banks, because the banks are where most of their food comes from, and on mid-river structure, sunken logs and weed beds especially. Some browns live in the river year-round and grow wary in the low clear water of late summer; others live in the lakes and move. In autumn, browns and landlocked salmon push out of the lakes into the rivers, and the biggest fish of the year are caught in those weeks. March and early April are the window, and Laguna Larga, fly-only and catch-and-release under the regulation and open to June 30, is where we point anglers hunting one big fish rather than many.
Rainbow trout: the volume fish
Rainbows are the most numerous fish in the system and the reason a first-timer can have a great week here. Like the browns they feed tight to the banks, and Diego's tip for finding the hungry ones is the big eddies and seams, where the current gathers the food and the rainbows gather under it. They rise willingly through the summer. January and February are their months for numbers, on the dry flies this water is known for. If your trip is about counting fish on a floating line, plan around the rainbows and treat every brown as the bonus.
Brook trout and the fourth fish
Brook trout live where the water runs coldest: the spring creek, the mouths of the tributaries feeding the main rivers, and the outlets into the lakes. Chubut has a quiet reputation among anglers for brookies that far outgrow their North American ancestors, and ours run around 14 inches, a serious brook trout by any standard. One regulation matters: from March 1, every brook trout caught in rivers and streams must be released. The fourth fish, the landlocked salmon, descends from the Sebago Lake eggs of the 1904 era. It lives in the lakes and the connecting water, runs 16 to 20 inches here, eats streamers, and is the least predictable thing that will pull on your line all week. Nobody plans a trip around one; everybody remembers the one they landed.
What they eat through the season
The fly box tells the same seasonal story as the fish. In spring, November and December, the workhorses are nymphs, stonefly, Prince, Hare's Ear and Montana patterns in 6 to 14, with the first mayfly, caddis and dragonfly hatches bringing fish up. High summer is dry fly water: Adams, Wulffs, Goddard Caddis, Humpies, Irresistibles, and hoppers in 10 to 16 along the grass banks. Autumn turns the big fish predatory, and streamers earn their place: olive and black Buggers, Matukas, Muddlers in 4 to 10, fished on a sinking tip around the lake mouths. The full gear picture is in our packing guide, fly fishing gear for Patagonia.
Why this water holds fish where others drop off
Free-flowing rivers boom and bust: snowmelt blows them out in spring and heat starves them in late summer. Lake-fed water does neither. The lakes buffer the flows, hold the temperature down, and keep the food factory running, which is why the fishing here stays steady across a six-month season instead of peaking for six weeks. It is also why the water runs clear enough that much of the fishing is sight fishing: you see the fish, the fish can see you, and the cast has to be honest.
The fish you will remember
The regulation keeps this honest: the Carrileufú is fly-only, catch-and-release water, so every fish in this article is still in the river. If you want the fuller picture of how a week on it is structured, float and wade, river by river, that is the job of our complete guide to the Carrileufú, and the lodges around Patagonia that fish very different water are compared in Patagonia fly fishing lodges, compared.
Check your dates
Send us the month and the number of anglers. We reply within one business day with the open weeks and what the water is doing that month.
What trout are in the Carrileufú River?+
Wild brown trout and rainbow trout, with brook trout in the colder corners of the system and landlocked salmon in the lakes and connecting water. All are self-sustaining populations descended from introductions in the early 1900s.
How big are the trout in the Carrileufú?+
Browns and rainbows run 12 to 21 inches with the average fish at 16 to 17, occasional fish over 22 (mostly browns), and last season's biggest a 23-inch brown. Brook trout run around 14 inches and landlocked salmon 16 to 20.
Are Patagonia trout wild or stocked?+
Wild. Nothing in this valley is stocked; the populations have reproduced on their own for more than a century.
When do the biggest brown trout run in Patagonia?+
In this system, autumn. From March into early April, browns and landlocked salmon move out of the lakes into the rivers, and the biggest fish of the year come in those weeks.
Is the Carrileufú catch and release?+
Yes, fly-only and catch-and-release under the Patagonian sport fishing regulation, and brook trout in all rivers and streams must be released from March 1.