Peixe-cachorro from Amazonian and Orinoco rivers: slender, silvery, with a pointed snout and sharp teeth, and a black band on the gill cover that looks like a collar. It attacks small mid-water lures and tends to show up as incidental catch.
Also called: peixe-cachorro, peixe-cachorro-amazônico, cachorro
Predator of the family Acestrorhynchidae, reaching about 45 cm. It lives in the channel and tributaries of clearwater and blackwater rivers in the Amazon (Brazil, Peru and Ecuador), the Venezuelan Orinoco and the coastal rivers of Guyana, and enters flooded areas at high water. It hunts fish in open water, by day, with conical teeth, and can attack prey large for its size. Juveniles travel in shoals; adults are more solitary. FishBase lists it in commercial fishing and among sport fish; anglers who fish predators with small lures may hook it.
fun facts
The black band on the gill cover gives the fish the look of a dark collar.
Juveniles form strong shoals and adults are more solitary.
In aquariums it is a powerful jumper and needs a very secure lid.
how to recognize it
identification
Slender, silvery fish with a pointed snout and a large mouth with conical teeth. The mark is a black fringe on the back edge of the gill cover, strongest in the upper half, which gives a 'collar' look, and a round black spot at the base of the tail. Juveniles have two dark stripes along the body that fade with age. It is much larger than the peixes-cachorro of the A. nasutus group, which do not exceed 10 cm, and it lacks the fangs that cross the snout of the cachorras (Hydrolycus).
how peixe-cachorro-amazônico fishing looks
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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.
Tributaries of the northern Amazon basin, in Brazil, Peru and Ecuador; also the Orinoco basin, in Venezuela, and coastal rivers of Guyana. In Brazil, it lives in the channel and in clearwater and blackwater tributaries.
Habitat: Channel and large clearwater and blackwater tributaries, in open water, near cutbanks and submerged timber; at high water it enters flooded areas. It is more a channel and open-water fish than a closed-lake fish.
native to the basins
Amazon
calendar and clock
when to fish
best season
time of yearbest: Jul–Nov
JanFebSeaAprMayJunJulAugSepOctNovDec
Falling water and dry season (August to November in central Amazonia): low river and fish concentrated in the channel and at lake mouths. At high water it spreads through flooded areas and fishing is poorer. The calendar changes from river to river.
best time of day
Daytime, with peaks at dawn and dusk. Hunts by day, most active early and late in the afternoon, in open water near cutbanks and submerged timber. At night it practically stops.
weather, water and behavior
what affects the peixe-cachorro-amazônico
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 weather helps; a storm shuts fishing down for a few hours.
moon
Small effect.
rain
Heavy rain muddies the water and scatters the fish; light rain does not get in the way.
water level
A falling river is the best scenario, with fish in the channel and at igarapé (creek) mouths. At high water it spreads through the flooded area.
noise
Moderate: approach cutbanks and submerged timber slowly.
wind
Little effect in the channel; strong wind makes casting difficult.
spinning reel 2500 to 3000 or low-profile baitcasting reel 100
line
braided 15 to 20 lb
leader
fine steel leader, 20 to 30 cm, or fluorocarbon 30 to 40 lb: the teeth cut thin line
hook
treble hooks No. 4 to 1/0 on artificial lures; hook 1/0 on natural bait; the mouth is hard and bony
lures
spoon, 5 to 14 g
spinner #2 to 3
minnow and jerkbait, 7 to 10 cm
feathered jig 1/8 to 1/4 oz
natural baits
live lambari
piece of fish
accessories
long-nose pliers
boga-grip
tip from an angler
Set the hook firmly and keep the line tight: the mouth is bony and the lure gets away easily. Remove the hook with long pliers, away from the teeth.
what the law says
rules for the peixe-cachorro-amazônico
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).
We found no species-specific rule beyond the region's general rules.
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.
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.
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.
Use long-nose pliers and keep the fish in or near the water; the teeth are sharp and the mouth is bony. Remove the hook quickly and release it facing the current.
in the kitchen
It shows up in commercial fishing. Like other characins, it has many fine bones, which is why it is usually fried or used in broths.
calculator
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.00759, b = 3.06; 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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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.
scientificFishBase: Acestrorhynchus falcirostris (ficha da espécie)Size, length-weight relationship, depth, habitat, distribution, biology and IUCN status. Page checked on October 13, 2026. The common size and weight and the depth range are editorial estimates for sport fish; the maximum weight was calculated from the length-weight relationship (FishBase gives no weight). Seriously Fish cites 32 to 35 cm standard length for maximum size; we kept FishBase's 45 cm.
technicalSeriously Fish: Acestrorhynchus falcirostrisHabitat, diet of a fish-eating predator, behavior, and characters that separate the species from its relatives (black gill-cover band, juvenile stripes). Page checked on October 13, 2026.
