peixe-anual-monstruoso
Titanolebias monstrosus · Rivulidae · omnivore
Freshwater annual killifish from the Paraguay River basin, in Argentina and Paraguay, reaching 15 cm. It is vulnerable and used in the aquarium trade.
Also called: peixe-anual-monstruoso, peixe-anual
- maximum
- 15 cm
the right time
to be on the water
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…
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hour by hour
slide your finger or mouse over the chart to see each hoursee hour-by-hour table
why this index at —?
choose the day
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.
the fishing month at a glance
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.
everything about the peixe-anual-monstruoso
who is the peixe-anual-monstruoso
The monstrous annual killifish is a freshwater fish of the family Rivulidae, reaching 15 cm. It occurs in the Paraguay River basin, in Argentina and Paraguay, in tropical water at 25 to 30 °C. It lives in the midwater and spawns on the bottom, and the eggs take three months to hatch. It is hard to keep in captivity, but it has commercial use in the aquarium and in fishing. Because it is vulnerable, its capture should be avoided and the fish released.
Essential profile. Identification, where it occurs and rules, with data from FishBase and the cited regulations. Season, time of day, technique and bait are added once we have a good source for the peixe-anual-monstruoso; in the meantime, see the similar species.
fun facts
- It is hard to keep in an aquarium, even with the trade in ornamental fish.
identification
Small, elongated fish of the family Rivulidae, reaching 15 cm. It can be confused with the elongated annual killifish (Titanolebias elongatus), which also lives in Argentina and reaches 22 cm. Like other annual killifish, it has a small, elongated body. The best clue is the range, in the Paraguay River basin, while the other lives in the Paraná–La Plata basin. This is the smaller of the two, and it also occurs in Paraguay.
where found
Paraguay River basin, in Argentina and Paraguay, in tropical freshwater.
Habitat: Midwater in tropical-water rivers of the Paraguay River basin. Spawns on the bottom.
rules for the peixe-anual-monstruoso
Summary of the regulations we found, with the source for each. Rules change; before keeping or transporting fish, check with the state environmental agency.
We found no species-specific rule beyond the region's general rules.
catch and release
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.
No known danger to anglers. Because it is vulnerable, release it with wet hands and without keeping it out of the water for long.
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.00603, b = 3.14; FishBase (relação peso-comprimento bayesiana, estimativa)). It's an average: a fat or lean fish can vary by 10% to 20%.
estimated weight
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sources and references
Essential profile: size, length-weight, depth, countries and conservation come from FishBase and the cited regulations, and the texts were written from those sources. Season, time of day, sensitivities, technique and baits and lures are not included yet, because we did not find a good source for this species.
- scientific FishBase: Titanolebias monstrosus (ficha da espécie)Size, length-weight, depth, habitat, distribution, biology, and IUCN status. Page checked on Oct 13, 2026.
- scientific FishBase: nomes populares de Titanolebias monstrosusNames by country and language.
similar species
where each number comes from
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.
sources for this lookup
how accurate the forecast is
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: