For a species of 0.5 to 2 kg that lives in cold streams and lagoons, the ideal gear is light and sensitive, allowing you to enjoy the fight and present small lures and flies with precision.

Spinning:

• Rod: ultralight to light, 1.60 to 2.10 m, fast action and light or ultralight power (for casting lures of 1 to 7 g).
• Reel: small front-drag (size 1000 to 2500), with a smooth, progressive drag, well adjusted so as not to break fine lines on the strike.
• Line: fine braid of 8 to 12 lb (or monofilament of 4 to 8 lb), which gives sensitivity and distance with light lures.
• Leader: fluorocarbon of 4 to 8 lb, barely visible in the crystal-clear waters where the brook trout is wary.

Fly:

• Rod: #3 to #5 line, 8 to 9 feet, is the most versatile for mountain streams and lagoons. For small, tight streams, a short #3/#4 rod is comfortable.
• Reel: a fly reel to match the line, with a click or smooth drag.
• Line: WF (weight forward) floating for dries and nymphs near the surface; sink-tip line or polyleader if you need to get streamers down.
• Tippet/leader: 4X to 6X (approximately 3 to 6 lb) depending on fly size and water clarity.

Round it out with barbless hooks if you are going to practice catch-and-release, a hook-removal tool (forceps), a soft-mesh (rubber) net so as not to harm the fish, and waders if you are going to wade into the cold water.

Gear is chosen according to the environment and the expected size. A versatile, concrete setup:

Spinning (general use, rivers and lakes):

• Rod: 1.80 to 2.10 m, medium / medium-fast action, light to medium power (4–12 lb line). For large lakes or very big browns, step up to medium-heavy.
• Reel: front-drag size 2500–3500, with a good drag and smooth retrieve.
• Line: braided line 0.12–0.20 mm (approx. 10–20 lb) for sensitivity and hookset power, or 8–12 lb monofilament in smaller environments.
• Leader: fluorocarbon 0.25–0.35 mm (approx. 8–15 lb), low-visibility and abrasion-resistant against rocks and structure. Go finer with the leader if the water is clear and the brown is wary… but beef it up if there is a lot of cutting structure.

Fly fishing:

• Rod: #5–#6 line for a medium river and dry/nymph fishing; #7–#8 for streamers, the Patagonian wind and large specimens.
• Reel: with a good drag and backing, matched to the line weight.
• Lines: floating (WF) for dry and nymph; sink-tip or full sinking line for streamers in pools and lakes.
• Tippet/leader: tapered ending in 3X–5X for dry/nymph; a stouter 0X–2X for streamers and big fish.

Recommended accessories: rubber net (less harm to the fish for release), forceps for removing hooks, barbless hooks, and waders for safe wading in cold water.

The gear is matched to the setting and the size of trout you are after, but these setups cover most situations in Argentina:

Spinning (general use, trout of 1 to 3 kg):

• Rod: 1.80 to 2.10 m, medium to medium-fast action, light to medium-light power (casting lures of roughly 3 to 12 g).
• Reel: front-drag, size 1000 to 2500, with a progressive, smooth drag—key to withstanding the runs and jumps without breaking off.
• Line: fine braid of 8 to 15 lb for its sensitivity and lack of stretch, or nylon/mono of 6 to 10 lb if you prefer something more forgiving for the hookset.
• Leader: a section of fluorocarbon of 0.20 to 0.28 mm; fluoro is less visible underwater, which matters in Patagonia's crystal-clear water.

Fly:

• 5-6 weight outfit: the most versatile for river rainbows in Patagonia (dries, nymphs, and small streamers). A 9-foot rod.
• 7-8 weight outfit: recommended for big-trout waters like Strobel/Barrancoso, heavy streamers, and strong wind.
• Leader and tippet: a 9-foot tapered leader finished in 3X to 5X tippet depending on the fly size and how selective the fish is.

For trophy specimens (5-10+ kg at the Strobel): step up the power—medium/medium-heavy spinning with 15-20 lb braid and a robust fluoro leader, or a 7/8 fly outfit—because these are fish with strength and runs far superior to the average trout.

In every case: a well-adjusted drag, sharp hooks (barbless if you are going to release), and a rubber net to handle the fish with the least possible harm.