Jaú
The jaú is one of the largest freshwater fish in South America — a massive pimelodid catfish that can push past 100 kg and 1. 5 m in the Amazon basin.
In Brazil it's a bucket-list target for sport anglers who make dedicated trips to Amazonian rivers, where the fish holds near rapids and feeds on migrating fish.
Its sheer size and the remote water it lives in make it one of the most demanding freshwater pursuits in the country.
Scientific Name: Zungaro jahu
Also known as jaú, pacamum, manguruyu
- Scaleless, smooth-skinned body ranging from dark brown to olive-gray on the back, fading to yellowish on the belly — no scales, just slick skin.
- Broad, flattened head with an enormous mouth built for swallowing whole prey; short barbels compared to other large pimelodids, but highly sensitive.
- Adults typically run 80 cm to 1.5 m; fish over 1.6 m and 120 kg have been recorded, making it one of the heaviest catfish in Amazonian waters.
- Distinguish from the pintado (spotted sorubim) by the lack of bold spots and the more uniformly dark, robust body shape.
What to know
Habitat Distribution
- Native to the Amazon basin; in Brazil it occupies the main channels and large tributaries of the Amazon, including blackwater systems like the Rio Negro and its tributaries such as the Rio Jaú.
- Adults live in deep river channels with muddy or sandy bottoms; juveniles can be found in flooded-forest margins during high water.
- A separate species, Zungaro jahu, is native to the upper Paraná basin in southeastern Brazil (São Paulo state and surrounding drainages) but is listed as endangered and has been recorded as an introduced fish in the Iguaçu basin above Iguaçu Falls — an alarming range expansion.
- The Jaú National Park in Amazonas state — a 2.27-million-hectare UNESCO World Heritage reserve — takes its name from this fish and protects core habitat in the Rio Jaú/Rio Negro system.
Key Locations
- Rio Negro and its tributaries (Amazonas state) — core Amazon habitat; the Rio Jaú within Jaú National Park is namesake water for the species.
- Upper Amazon main channel and large tributaries near the Brazil-Peru-Colombia border region — historically the highest-yield area for jaú in commercial catch data.
- Central Amazon around Manaus — accessible staging point for sport fishing expeditions targeting jaú in main-channel and tributary water.
- Carabinani rapids (Rio Negro/Jaú National Park area) — a known concentration point where the fish stage to intercept migrating prey.
Specific Spots
- Cataracts and rapids are the most productive holding water: jaú stage below and around falls to intercept migratory characins (such as dourado and matrinxã) moving upriver.
- Deep channel edges adjacent to fast water — the fish rest in slower, deeper water and move into current to feed, so work the seam between fast and slow flow.
- Submerged structure (fallen timber, rock ledges) in main-channel depths gives jaú a place to hold during daylight hours; night fishing over these features is most productive.
Jaú FAQ
Answers from onWater's species guide.
What are the best lures and bait for Jaú?
Large live or freshly cut baitfish are the go-to: whole fish or large chunks presented on the bottom near rapids and current breaks directly match what jaú are hunting.
When is the best time to fish for Jaú?
Low water and early rising water (roughly July–November in the central Amazon) concentrate jaú near rapids and cataracts, the most productive window for sport fishing. As water rises and floods the forest margins (December–March), fish disperse and become harder to locate in main channels.
How do you catch Jaú?
Anglers in Brazil pursue jaú almost exclusively by boat, anchoring or drifting near rapids and deep channel edges in large Amazonian rivers. The standard method is bottom fishing at night with large live or cut baitfish on heavy tackle, targeting the seams between fast and slow current where the fish hold and feed.
What do Jaú eat?
Primarily fish-eating: jaú prey heavily on migratory characins, dourado, matrinxã, and similar schooling species, which is why rapids and cataracts concentrate them. Large whole or cut fish baits that match this forage are the standard approach.
Where do Jaú live?
Native to the Amazon basin; in Brazil it occupies the main channels and large tributaries of the Amazon, including blackwater systems like the Rio Negro and its tributaries such as the Rio Jaú.
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