Mylossoma duriventre · Serrasalmidae · omnivore
Small, silvery, flattened pacu with a black spot on the gill cover, from the Plata basin. It eats fruit and seeds, nibbles small hooks, and has a 20 cm minimum size in the Pantanal.
Also called: pacu-peva, pacupeba, pacu-peba, pacu-comum
Choose the place and the species. The index, from 0 to 100, combines weather, sun, moon and tide with each fish's habits. Up to 28 days, with each day's confidence.
Reading the weather across 3 global models and 31 simulations…
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.
Choose how many fishing days. We compare each stretch by its average index, discount days with a warning or closed season, and show the 3 best.
Line: the middle value of 31 simulations of the American GEFS model. Band: where 8 out of 10 fall. Narrow, firm trend; wide, high uncertainty.
Small disc-shaped pacu, up to about 25 cm and 1 kg, now restricted to the Plata basin (Paraguay, lower Paraná and lower Uruguay rivers) after the Mateussi et al. (2018) review separated the Amazonian forms (M. albiscopum and M. aureum) and the Tocantins-Araguaia form (M. unimaculatum). FishBase describes it as herbivorous, very dependent on floodplains and of great importance in commercial and sport fishing, and lists it as potamodromous, that is, migrating within rivers. Juveniles eat insects and adults eat fruit and seeds. In the Pantanal and MS it is the pacu-peva, with a 20 cm minimum size, and Goiás treats it as an introduced species in the Paranaíba. Pacu-manteiga is the name FishBase gives it, but in the Amazon the name belongs to another species (M. albiscopum).
Disc-shaped, very compressed, silvery body with a very visible black spot on the gill cover and a keel with spines on the belly, the last one reaching the origin of the anal fin. The anal fin has 26 to 32 branched rays, and the lateral line has 74 to 98 scales. The Amazonian pacu-manteiga (Mylossoma albiscopum) has more anal rays (31 to 38), and M. aureum, from the Amazon, has almost no spot on the gill cover. Lower and smaller than the pacu and the pirapitinga.
Paraguay floodplain (Pantanal), in MT and MS. Outside Brazil, lower Paraná and lower Uruguay, in Argentina, Paraguay and Uruguay. Goiás lists it as introduced, of unknown origin, in the Paranaíba.
Habitat: Rivers, bays and lagoons of the Pantanal floodplain; it enters flooded vegetation at high water (due to its dependence on várzeas, as FishBase notes).
native to the basins
introduced in
states
Mato Grosso, Mato Grosso do Sul, Goiás
Estimate: falling water and dry season (July to October in the Pantanal) concentrate shoals in bays and channels; at high water the fish spreads out. Check your state's closed season in the general rules.
Daytime. Feeds by day, most active early and late in the afternoon (estimate).
Cold knocks activity down for a few days.
Stable pressure helps.
Little known effect.
Light rain doesn't bother it.
Falling water concentrates the school.
Wary: approach quietly.
Little effect.
Shallow to mid-water, 0.5 to 3 m.
natural baits
accessories
Bait on the float, close to the vegetation on the bank. Strike quickly: it nibbles and lets go.
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 Brazilian national list (Ministerial Ordinance GM/MMA No. 1.667/2026).
In the Alto Paraguay basin, in Mato Grosso, pacu-peva (listed as Mylossoma paraguayensis, same as M. duriventre) may only be caught at 20 cm or longer. Recreational fishing in MT is catch and release, with retention of up to 2 kg or 1 fish for consumption on site, within 500 m of the river (art. 19-C of Lei nº 9.096/2009).
In Mato Grosso do Sul, pacupeva (Mylossoma paraguayensis) has a 20 cm minimum size, with no maximum size. Recreational fishing is catch and release, with 1 native-species fish for transport, observing the sizes in the decree (art. 4º, I).
Source: Decreto estadual MS nº 15.375/2020, art. 9º (amends Decreto nº 15.166/2019)
In the Paranaíba basin, in Goiás, pacu-manteiga (Mylossoma aff. duriventre) is on the list of introduced species of unknown origin, and can be caught, kept and transported with no size or quantity limit. Fish from this catch may not be sold or processed, and a fishing license remains mandatory.
Source: Instrução Normativa Semad-GO nº 17/2026, art. 5º and Annex II (Paranaíba basin)
In the Colombian Orinoquia, palometa of the genus Mylossoma (the AUNAP compilation lists M. duriventre) has a minimum catch size of 24 cm standard length. The 1981 text refers to Mylossoma sp.; check the scientific name and validity with AUNAP before fishing.
Allowed: Subsistence fishing by riverside residents and authorized scientific fishing. Decree 15.166/2019 (art. 11, §5) allows catch and release only in February and only in the channels of the Paraguay and Paraná rivers. For the rest of the period, not even catch and release is allowed. Check the Imasul portaria for each season.
Source: Decreto estadual MS nº 15.166/2019, art. 11; IN IBAMA nº 201/2008
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.
Small, hardy fish: remove the hook in the water and release it.
Fatty, tasty meat from small pacu; fried or grilled over embers. Counts as the native fish in the recreational angler's bag limit in MS.
Length-weight relationship W = a·Lb (a = 0.02512, b = 3.03; FishBase (relação peso-comprimento bayesiana, estimativa da própria espécie)). 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.
The weather comes from three independent global models, cross-checked hour by hour: when they agree, confidence goes up; when they diverge, the band between them shows on the chart. Beyond 16 days, we use the GEFS ensemble of 31 simulations: if 20 of the 31 predict rain, the chance of rain is 65%. Sun and moon are calculated astronomically, with no uncertainty.
The index adds up, weighted for each species: time of day (species curve anchored to real sunrise and sunset), moon (transits, rise and set, phase), pressure (3 h trend and 24 h swing), water temperature (in rivers, estimated from air temperature; at sea, estimated by an ocean model), wind, rain, clouds, tide and the month in the species' cycle.
Accuracy measured in the reference project (4 regions, 93 days, forecast vs. observed): maximum temperature is off by 0.6 °C on average the next day and 1.7 °C at 7 days; rain of 5 mm or more is detected 76% of the time the next day and 57% at 7 days. Detection isn't everything: the false alarm rate isn't published here yet, and 93 days in 4 regions is still a small sample. We now also measure every day, at the app's destinations:
Your location is saved only on this device and feeds the forecast, the map and the "today" on the home page.
