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fishing forecast

redhook myleus

Myloplus rubripinnis · Serrasalmidae · omnivore

Freshwater

Silvery pacu with a red anal fin with a black edge, from calm waters with vegetation over the bank. It eats leaves of river plants, moves in shoals and bites hard.

Also called: pacu-branco, pacu-tinga, pacu

everything about the redhook myleus where found
Scientific illustration of Redhook myleus
common size
20–32 cm
maximum
42 cm
common weight
0.2–0.7 kg
record/max.
2.5 kg
depth
0.5–6 m
ideal water
24–28 °C
location

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period

Reading the weather across 3 global models and 31 simulations…

the species

everything about the redhook myleus

overview

who is the redhook myleus

Medium-sized, disc-shaped pacu that lives in shoals in the calm parts of large rivers, where vegetation hangs over the bank. According to FishBase, it is gregarious and not very aggressive, but has powerful teeth capable of serious bites; adults eat leaves of river plants. The red anal fin, hook-shaped in adults (hence 'redhook' in English), plays a role in spawning: the female uses it to dig a furrow in the gravel while the male wraps his bilobed anal fin around her. It reaches 41.5 cm and 2.5 kg and has a minor commercial fishery. Taxonomy is complex: Myloplus rubripinnis and M. asterias are very similar, and recent research restricts M. rubripinnis to the Guiana Shield, treating the pacu of Brazilian Amazonia under that name as a possible undescribed species.

fun facts

  • The female's red anal fin works like a plow: she digs a furrow in the gravel while releasing eggs, and the male wraps his bilobed anal fin around the hook-shaped part (FishBase).
  • The species was described from Guyana, and the Amazonian populations may be a different species (Ota et al., 2020).
how to recognize it

identification

Tall, disc-shaped, silvery pacu with a red anal fin with a black edge, which in adults is hook-shaped. Small head, serrated keel on the belly and strong crushing teeth. It lacks the vertical black bar of the pacu-cadete (Myloplus schomburgkii) and the black spot on the gill cover of the pacu-peva (Mylossoma duriventre). Telling M. rubripinnis from M. asterias uses dorsal fin rays and the shape of the fontanelle, and is not done in the field.

distribution

where found

open on the large map

Amazon and Orinoco basins and rivers of the Guiana Shield. In Brazil, M. rubripinnis in the strict sense occurs in the rivers of the Guiana Shield (Araguari, Jari, Oiapoque); populations of Brazilian Amazonia, such as those of the Tapajós, previously called by this name, are now treated as a possible undescribed species (Ota et al., 2020).

Habitat: Calm parts of large rivers, where vegetation hangs over the bank; also tributaries with dense vegetation (estimate based on the leaf-eating habit of pacus).

native to the basins

Amazon

states

Amapá, Pará, Amazonas

calendar and clock

when to fish

best season

time of yearbest: Jul–Nov
JanFebSeaAprMayJunJulAugSepOctNovDec

Estimate: falling water and dry season concentrate shoals in eddies with vegetation. At high water the fish spreads through the flooded forest.

best time of day

0h6h12h18h sunrise ~6amsunset ~6pm

Daytime. No timing studies. Like pacus in general, it feeds by day (estimate).

weather, water and behavior

what affects the redhook myleus
sensitivity The little bars show how much each factor affects this species. Five full: it feels it a lot.

cold and cold fronts

Cold snaps (friagem) shut down activity for a few days.

atmospheric pressure

Stable pressure helps.

moon

Little known effect.

rain

Light rain doesn't bother it.

water level

A falling river concentrates the shoal under the vegetation.

noise

Seriously Fish describes it as somewhat nervous: approach quietly.

wind

Little effect.

depth

Mid-water and near the bank, 0.5 to 4 m.

technique, gear and bait

how to fish

Caniço (cane pole)Natural bait with float
rod
bamboo pole 3 to 4 m or rod 5'6" to 6', 8 to 15 lb
spinning / baitcasting reel
spinning reel 1000 to 2500
line
monofilament 0.25 to 0.30 mm
leader
fluorocarbon 30 lb, 30 cm: the teeth cut thin line
hook
No. 2 to 1/0, strong, short shank

natural baits

  • fruit and leaves from the bank
  • boiled corn
  • flour dough

accessories

  • small float
  • long-nose pliers

tip from an angler

Plant bait on the float, right against the vegetation hanging over the water (estimate based on its leaf-eating habit). Set the hook fast and use a leader: the bite hurts.

what the law says

rules for the redhook myleus

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).

PA and AP: the portaria cites 'pacu (Myleus spp.)' in the closed season

fishing banned Nov 15 to Mar 15 for 'pacu (Myleus spp.)'; application to the genus Myloplus not confirmed15/11 to 15/03PAAPAmazonconfirm with the agency

The portaria bans fishing for 'pacu (Myleus spp. and Mylossoma spp.)' in PA and AP, from Nov 15 to Mar 15. Myloplus are not named and have already been classified as Myleus; applying the ban to them depends on the agency's interpretation. Under art. 2º, II, the recreational angler using handline or rod is exempt, unless a stricter state rule applies. When in doubt, check with the state agency.

Source: Portaria IBAMA nº 48/2007, Annexes I and II

piracema closures in the basins where the species lives

Spawning closure (piracema) in Mato Grosso (all basins)

01/10 to 31/01MT

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.

Source: IN Interministerial MAPA/MMA nº 10/2017; Resolução Cepesca-MT nº 1/2026; Lei estadual MT nº 9.096/2009, arts. 19-A and 27 (Leis 12.434/2024 and 13.159/2025)

Closed season in the rivers of Marajó Island (PA)

01/01 to 30/04PA

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

Closed season in the Amazon basin in Amapá

15/11 to 15/03AP

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

Border rivers MT/RO and MT/PA

05/11 to 28/02MTROPA

Allowed: See the exceptions in Portaria 48/2007 and the state rules for each bank.

Source: Portaria IBAMA nº 48/2007

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.

Hold it from below, with a damp cloth and away from the mouth: the teeth crush and cut. Remove the hook with long-nose pliers and return the fish to the water.

in the kitchen

FishBase lists it as a minor commercial fishery species. Pacu meat, good baked or fried; we found no market notes specific to the species.

calculator

how much it weighs without taking it out of the water

Length-weight relationship W = a·Lb (a = 0.02344, b = 2.97; 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

—

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.

  1. scientific FishBase: Myloplus rubripinnis (ficha da espécie)Size, length-weight relationship, depth, habitat, distribution, biology and IUCN status. Page checked on October 13, 2026. The maximum weight of 2.5 kg is the one published in FishBase; the common sizes and weights on this card are editorial estimates, calculated from the length-weight relationship.
  2. scientific FishBase: nomes populares de Myloplus rubripinnisNames by country and language.
  3. official Portaria GM/MMA nº 1.667, de 27 de abril de 2026: Lista Nacional Oficial de Espécies da Fauna Ameaçadas de Extinção (peixes e invertebrados aquáticos)The species is not on the list. Checked in the DOU of April 28, 2026.
  4. scientific IUCN Red List: Myloplus rubripinnis (avaliação global: Pouco Preocupante, LC, 21/12/2020)Global assessment. Link given on the FishBase entry (Red List, version 2025-2).
  5. scientific Ota, R. P.; Machado, V. N.; Andrade, M. C.; Collins, R. A.; Farias, I. P.; Hrbek, T. (2020). Integrative taxonomy reveals a new species of pacu (Characiformes: Serrasalmidae: Myloplus) from the Brazilian Amazon. Neotropical Ichthyology 18(1): e190112.Difficulty separating M. asterias and M. rubripinnis; M. rubripinnis restricted to the Guiana Shield, and Brazilian Amazonian pacus treated as M. aff. rubripinnis. Text checked on October 13, 2026.
  6. technical Seriously Fish: Myloplus rubripinnisRed anal fin with a black edge, herbivorous and shoaling habit, slow rivers with dense vegetation. Page checked on October 13, 2026.
  7. official Portaria IBAMA nº 48/2007: defeso na bacia do rio AmazonasAnnex II: pacu (Myleus spp. and Mylossoma spp.) in Pará and Amapá during the closed season. Myloplus are not named. Page checked on October 13, 2026.
don't confuse

similar species

Illustration of Pacu-manteiga
Serrasalmidae

Pacu-manteiga

Mylossoma albiscopum

A small, silver pacu from the Amazon várzea, one of the best-selling fish in Amazonas markets. It eats fruit and seeds and nibbles small hooks.

Freshwater
time of yearbest: Aug–Nov
Illustration of Black pacu
SerrasalmidaeVU

Black pacu

Colossoma macropomum

A major eater of Amazonian fruits and seeds and a mainstay of national fish farming. Since 2026 it is listed as Vulnerable on the national list.

Freshwater
time of yearbest: Apr–May
Illustration of Disk tetra
Serrasalmidae

Disk tetra

Myloplus schomburgkii

Disc-shaped, silvery pacu with a vertical black bar on the flank. From the Amazon and the upper Orinoco, it eats fruit and seeds and gives serious bites to anyone who holds it carelessly.

Freshwater
time of yearbest: Jul–Nov