The tiger sorubim is a big, strong fish that fights in current and against structure, so you need robust, reliable gear. The rule is not to underestimate it: a medium fish in current already demands a lot from your tackle.

For bottom fishing / drifting with bait:

• Rod: medium-heavy to heavy action, 1.80 to 2.40 m, with good reserve power to lift a fish out of the hole. One-piece or two-piece, with reinforced guides.
• Reel: a rotating reel (a good-sized baitcaster) or a robust spinning reel, with a good drag and line capacity. The drag has to be smooth but powerful to withstand the runs.
• Line: braid of 0.30 to 0.40 mm (approx. 40 to 65 lb), which gives you sensitivity to detect the bite on the bottom and power to fight. Alternatively, monofilament nylon of 0.50 to 0.60 mm if you prefer the cushioning of nylon.
• Leader: essential. Use a section of fluorocarbon or heavy nylon of 0.60 to 0.90 mm, or even fine wire/steel, at least 40 to 60 cm long, to resist the chafing against the hard mouth, the structures, and the fish's skin. The sorubim doesn't cut with teeth like a tararira, but its mouth sands down the line.
• Hooks: strong, eagle-claw / O'Shaughnessy type 6/0 to 9/0, always well sharpened. If you fish catch and release, consider circle and barbless hooks (or with the barb pinched down) for a safer unhooking.
• Sinker: matched to the current, of a type that rests on the bottom without dragging too much.

For spinning with lures:

• Medium-heavy spinning rod of 1.80 to 2.10 m, with the power to cast large lures and fight in current.
• Spinning reel 4000 to 6000 with a good drag, loaded with 30 to 50 lb braid.
• Fluorocarbon leader 0.60 to 0.80 mm ahead of the lure.

Always add long pliers for unhooking, gloves to handle the fish safely, and a net or lip grip to hold it without hurting it if you're going to release it.

The surubí is a large, powerful fish caught in fast-flowing rivers with structure, so the tackle has to be up to it. Concrete recommendations:

For bottom fishing / drifting with bait:

• Rod: powerful, with medium to medium-fast action and good power (roughly 30-50 lb line class), 1.80 to 2.10 m, with backbone to lift weight off the bottom.
• Reel: a solid baitcaster or a large spinning reel (size 6000-8000), with a strong, progressive drag to withstand runs.
• Line: braid of 0.40 mm and up (approx. 50-80 lb) for its strength and sensitivity; or 0.50-0.60 mm monofilament if you prefer some stretch for cushioning.
• Leader: a section of thick monofilament or fluorocarbon (0.80-1.00 mm) or even flexible wire, to resist abrasion against the hard mouth, the structure, and the bottom.
• Sinker: matched to the current (pear, olive, or bottom sinker with a flag arm), of the weight needed to hold the bait.
• Hooks: strong and good-sized, reinforced O'Shaughnessy or circle types, matched to the size of the bait and the fish.

For spinning / trolling with lures:

• Rod: powerful spinning or baitcasting rod (20-50 lb line class), with a tip action to throw large lures and backbone to fight.
• Reel: spinning 5000-8000 or a robust baitcaster, with a good drag.
• Line: braid 40-65 lb, with a thick fluorocarbon leader (0.70-0.90 mm) or wire to avoid cut-offs.

In every case, the rule is oversize rather than come up short: a surubí of over 20 kg in full current, trying to bury itself in the logs, forgives neither weak tackle nor loose knots. Always check the condition of your line, your knots, and the sharpness of your hooks before each outing.