Zungaro zungaro
Giant, stocky catfish of deep pools and rapids. One of the strongest freshwater fish in Brazil.
Also called: jaú
The jau is a stocky catfish with a huge head and thick body, living in deep pools below rapids and waterfalls and in channels of large rivers. It hunts fish at night and spends the day hidden among rocks. It grows slowly and lives many years, so big ones are rare and should be released. In sport fishing it is the toughest opponent: once hooked, it hugs the bottom and uses weight and current to its advantage, and the fight can last a long time. It requires very heavy tackle and patience. In the Amazon and Araguaia there are still specimens over 50 kg.
Thick, short body for its size, very wide and flat head, huge mouth. Brown to olive color with dark blotches and spots, more marked in juveniles; pale belly. Small eyes and long barbels. The redtail catfish has a red tail and yellow band. The piraíba is more elongated and grey. The jau of the Plata is another species, from the Paraná basin.
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Each card shows the day's index (0 to 100) and, below it, a strip with the index for each hour, from 0h to 23h. from poor to excellent.
Amazon and Araguaia-Tocantins basins, especially the rapids pools of the Araguaia, Tocantins, Xingu, Tapajós, Teles Pires and Madeira rivers.
Habitat: Deep pools below rapids and waterfalls, channels with rocks and logs, deep backwaters.
native to the basins
states
Amazonas, Pará, Mato Grosso, Tocantins, Rondônia, Acre, Roraima, Amapá, Goiás
Dry season, June to October, when the pools below the rapids become well defined.
Nighttime. Feeds mainly at night. By day it stays hidden and only takes a bait placed well in the pool.
A cold snap (friagem) reduces activity.
A pressure drop before rain can trigger it.
Dark nights tend to produce more.
Little effect.
Low water concentrates jau in the pools.
Not very sensitive in rapids.
Little effect.
Pool bottom, 5 to 25 m.
lures
natural baits
accessories
When the jau sticks to the bottom, don't give it slack: keep constant pressure and change the boat's angle to pull it off the rock.
Summary of the regulations we found, with the source for each. Rules change; before keeping or transporting fish, check with the state environmental agency.
Conservation: Not on the national list (Portaria GM/MMA 1.667/2026). Slow growth makes large individuals vulnerable to fishing.
Until Dec 31, 2028, jau caught in rivers of Mato Grosso may not be transported, stored or sold. Recreational anglers may only practice catch and release.
Source: Lei estadual nº 12.434/2024 (MT), arts. 19-B and 19-C of Lei 9.096/2009
In Tocantins the jau may only be kept between 80 and 120 cm. Large ones go back into the water.
Source: Portaria NATURATINS/GABIN nº 47/2026 (annexes amended by Portaria nº 105/2026)
Transport, storage and sale are fully prohibited for 5 years from Jan 1, 2024 for: cachara, caparari, dorado, jaú, matrinchã (Brycon spp.), pintado/surubim (Pseudoplatystoma spp.), piraíba, piraputanga, pirarara, arapaima (pirarucu), trairão and peacock bass (tucunaré, Cichla spp.). For recreational anglers: catch and release only. These 12 species may not even be eaten on site, since the 2 kg or 1 fish limit excludes the art. 19-B list. The law cites jaú as Zungaro zungaro; we also include the Pantanal jaú (Z. jahu) out of caution. The list may still change: § 2 (exotic and predatory species), § 3 (review through study) and the 3-year assessment planned for 2027. A TJMT news report of Jun 2, 2026 confirms the 12 prohibited species. The STF denied a preliminary injunction in the ADIs against the law in 2024; we found no merits ruling.
Source: Portaria Naturatins nº 47/2026, Annex I, as amended by Portaria nº 105/2026
Source: INIs MPA/MMA nº 12/2011 (Araguaia) and 13/2011 (Tocantins), minimum size annexes
Allowed: Sport and guided fishing only in reservoirs, catch and release with barbless hooks (no keeping, transporting or eating). Subsistence: up to 5 kg per day, for household consumption only.
Allowed: All fishing modalities are prohibited in rivers, including catch and release (Law 9.096/2009, art. 19-A). Exceptions: subsistence fishing from shore (3 kg or 1 fish, no transport or sale) and scientific fishing. Law 13.159/2025 now allows licensed sport fishing in UHE/PCH hydropower reservoirs, natural lakes and border rivers, subject to a scientific study and a license from the environmental agency. We have not confirmed whether these licenses are already being issued.
Allowed: Recreational fishing only in reservoirs, with handline, rod, or spinning or baitcasting reel. Fish may only be eaten on site, not transported. Competitions prohibited. Subsistence: 3 kg + 1 fish. State rules (GO and TO) may be stricter.
Allowed: Recreational fishing only in reservoirs, with on-site consumption. Subsistence: 5 kg + 1 fish. State rules may be stricter.
Allowed: In 2025/26: catch and release with barbless hooks and recreational fishing card; subsistence fishing on foot or from a rowboat, with simple pole or handline.
Source: Portaria Naturatins nº 244/2025 (2025/26 season); INIs MPA/MMA nº 12 and 13/2011
Allowed: The same recreational-angler exceptions as in Portaria 48/2007 apply (handline or rod, 5 kg + 1 fish), unless a stricter state rule applies.
Source: Portaria IBAMA nº 48/2007
Allowed: Recreational anglers with handline or rod, line and hook are outside the Annex II prohibitions, with a bag limit of 5 kg + 1 fish, unless a stricter state rule applies.
Source: Portaria IBAMA nº 48/2007
Allowed: Subsistence fishing only.
Source: Portaria IBAMA nº 48/2007
Allowed: See the exceptions in Portaria 48/2007 and the state rules for each bank.
Source: Portaria IBAMA nº 48/2007
Keep the jau in the water; a fish over 40 kg should not be lifted. Hold it by the mouth with a thick glove, support its belly and release it in the pool where it was caught.
Fatty flesh; in the Amazon many consider it "reimosa" (strong-tasting). A fish to release.
Length-weight relationship W = a·Lb (a = 0.01514, b = 3.03; FishBase (bayesiano, espécie + forma do corpo da família)). It's an average: a fat or lean fish can vary by 10% to 20%.
estimated weight
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The season weights (months), the time of day and the sensitivities (cold, pressure, moon, wind, rain, tide, strong light, murky water and noise) are the app's editorial estimates, based on the literature below and on the field experience of anglers and guides. They are not official data nor a measurement made for this species, and they may vary by region and year. Closed seasons and legal rules appear in the rules section, with the norm and a link.
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