Ctenopharyngodon idella · Xenocyprididae · omnivore
A large herbivorous carp from China, raised in farm ponds and pay lakes. It exceeds 30 kg and gives one of the longest fights in lake fishing.
Also called: carpa-capim, carpa-chinesa, carpa-herbívora, carpa-do-limo
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.
Native to East Asia (China and the Amur River basin), the grass carp (carpa-capim) is one of the most farmed fish in the world and is also used to control aquatic plants in ponds and canals. It eats submerged plants and grass that falls into the water, and sometimes debris and invertebrates. It tolerates large temperature swings and low-oxygen water. In Brazil it is raised in farm ponds, private reservoirs and pay lakes, where it reaches large sizes. Goiás and Mato Grosso do Sul rules treat it as exotic, free capture. It demands heavy tackle and patience: it runs far and takes a long time to tire.
Elongated, rounded body with large dark-edged scales that form a net pattern; olive-green back and golden-silver flank. Mouth at the tip of the snout, no barbels, short snout and broad head. The common carp has barbels and a deeper body; silver and bighead carps have low-set eyes and small scales.
Exotic, native to East Asia. Raised in farm ponds, reservoirs and pay lakes; listed as exotic by the GO (Paranaíba and Araguaia-Tocantins) and MS rules, and recorded in the fish catalog of the upper Uruguay River.
Habitat: Farm ponds, reservoirs, pay lakes and eddies with aquatic vegetation.
introduced in
states
São Paulo, Paraná, Minas Gerais, Goiás, Mato Grosso do Sul, Santa Catarina, Rio Grande do Sul
famous destinations
Spring and summer. In the southern winter it eats little.
Daytime, with peaks at dawn and dusk. Feeds by day, most active early and in late afternoon; on hot days also at night.
Below about 15 °C it eats very little.
A cold front shuts down activity.
Little effect.
Little effect.
Little effect in farm ponds.
Very wary: noise on the bank scares the fish away.
Little effect.
Mid-water and surface, 0.5 to 3 m.
natural baits
accessories
Keep quiet on the bank and use vegetable bait on the surface or mid-water. Soft drag: the first run is long.
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: In its native range, the global IUCN assessment is Least Concern (LC, Mar 30, 2020).
In Goiás the grass carp is in Annex II of the state rule: exotic, allochthonous and hybrid species may be collected, killed and transported without size or bag limits, even with the zero transport quota for native fish.
Source: IN Semad-GO nº 17/2026, art. 5º and Annex II (exotic, allochthonous and hybrid species)
In MS carp (all species) are on the list of exotic, allochthonous and hybrid species whose specimens may be added to the angler's bag limit, subject to the closed season.
Introducing an exotic species without a technical opinion and license is a federal environmental offense. This includes releasing a fish from a tank, pay lake or aquarium into a river or reservoir.
Source: Lei federal nº 9.605/1998, art. 31, and Decreto federal nº 6.514/2008, art. 25
Large fish: use a landing net, wet your hands, support the body and release quickly. Do not release it into another body of water.
White flesh with Y-shaped bones; good baked, fried in chunks or as scored fillets.
Length-weight relationship W = a·Lb (a = 0.00933, b = 3.09; FishBase). 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.
