Exotic African fish, found in almost every small farm pond and reservoir in Brazil. Easy, fun fishing on light tackle. Never release it into a river or lake.
Also called: tilápia, tilápia-do-nilo, saint-peter (filé)
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.
location
Sample location: choose yours to see the forecast for where you fish.
period
Reading the weather across 3 global models and 31 simulations…
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index Score from 0 to 100 for the fishing conditions of each hour. It reads weather, sun, moon, tide and the species' habits. It doesn't promise fish: it tells you when the water is on your side. 0–24 poor · 25–44 fair · 45–64 good · 65–84 very good · 85–100 excellent.
today
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confidence —
confidence How much you can trust the weather forecast for the day. It drops with distance and when the models disagree. It is not the chance of catching fish.
models and trend Up to 16 days, three global weather models (the European ECMWF, the American GFS and a high-resolution blend) read hour by hour; when they disagree, the light band on the chart widens. Beyond that it's a trend: 31 runs of the American GEFS model. Confirm when it's 1 week out.
window Consecutive hours with the index near the day's peak and no danger alert. It is the time to have the bait in the water.
hour by hour
tap or drag on the chart to read each hour · on a keyboard, arrow keys
see hour-by-hour table
why this index at —?
next 7 days
choose the day
chart: bar height = day's index · line = variation between models · striped = trend · fainter = less confidence
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.
4-week calendar
the fishing month at a glance
plan a trip
what's the best window for the crew?
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.
trend for the coming weeks
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.
the species
everything about the nile tilapia
overview
who is the nile tilapia
African cichlid brought into fish farming, now the most farmed fish in Brazil. It escaped and established itself in reservoirs, lagoons, small farm ponds and rivers in nearly every basin. It is exotic: it competes with native fish, takes over nests and alters the environment. That is why releasing tilapia into a river, lake or reservoir without a license is an environmental offense. For anglers it is guaranteed fun on light tackle, with dough, feed or micro lures. It eats plankton, algae, pellet feed and small invertebrates. In several states it can be fished even during the piracema (spawning closure), according to local rules.
fun facts
The female incubates eggs and fry in her mouth.
It is the most produced fish in Brazilian fish farming.
Exotic: releasing tilapia into a river or reservoir without a license is an environmental offense.
how to recognize it
identification
Tall, compressed body, grey-olive to silver, with faint dark vertical bands. Trademark: regular black vertical stripes on the tail fin. Long dorsal fin with spines in front. Males in breeding have a reddish throat and fins. Native cará species do not have the regular stripes on the tail.
Exotic, originating in Africa and the Middle East. Established in reservoirs, small farm ponds, lagoons and rivers in nearly every Brazilian basin; large reservoirs of the Paraná, São Francisco and Northeast.
Habitat: Still, warm water: reservoirs, small farm ponds, lagoons, slack water and shallow vegetated banks; floating net pens.
São Paulo, Minas Gerais, Goiás, Paraná, Santa Catarina, Rio Grande do Sul, Mato Grosso do Sul, Mato Grosso, Bahia, Pernambuco, Ceará, Rio Grande do Norte, Paraíba, Espírito Santo, Rio de Janeiro, Tocantins, Maranhão, Piauí, Alagoas, Sergipe, Distrito Federal
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: Exotic species: management aimed at preventing new releases.
Releasing it into the natural environment without a license is an offense
releasing or introducing fish into rivers, reservoirs and lakes is prohibitedSPMGGOPRSCRSMSMTBAPECERNPBESRJTOconfirm with the agency
Introducing an exotic species, or one outside its natural range, without a technical opinion and a license is a federal environmental offense. This includes releasing a fish from a tank, pay lake or aquarium into a river or reservoir. In MG, the IEF states that stocking without a license is prohibited.
MT: introducing an exotic species without a license carries a fine
fine of R$6,000 to R$100,000MT
Mato Grosso's fishing law penalizes anyone who introduces native, exotic or non-native species without authorization from the environmental agency, with a surcharge per kilogram or per fish.
specimens may be added to the limit, subject to the closed seasonMS
In MS, tilapia is on the list of exotic, allochthonous and hybrid species whose specimens may be added to the angler's limit (1 native + 5 piranhas), subject to the closed season.
MT: catch and transport of exotics have their own rules
under Cepesca Resolution No. 02/2024MT
Cepesca Resolution No. 02/2024 regulates the catch and transport of exotic fish in the rivers of the Paraguay, Amazon and Araguaia-Tocantins basins in MT. Check with Sema-MT on the municipalities and conditions before transporting.
PR: exotics allowed; returning them to the water is restricted
exotics may be caught freely; confirm the release rulePRParanáSoutheast Atlanticconfirm with the agency
In PR, non-native fish may be caught in the interior basins. Portaria IAT 650/2025 sets a rule on releasing non-natives, with an exception for catch-and-release events aimed at them. Confirm with IAT before returning the fish to the water.
catch and release Releasing the fish alive, quickly and with a wet hand. During a closed season it isn't always allowed: what the regulation says applies.
Exotic: do not return it to environments where it does not yet exist. Where local rules allow it, prefer to kill it for food.
in the kitchen
White fillet, firm and boneless; fried, baked or grilled. It is the "saint-peter" of the market.
calculator
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.01778, b = 2.99; FishBase). It's an average: a fat or lean fish can vary by 10% to 20%.
estimated weight
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sources and references
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:
where are you going fishing?
Your location is saved only on this device and feeds the forecast, the map and the "today" on the home page.
