Rhaphiodon vulpinus
Long fish, flattened like a blade, with a mouth full of canine teeth. Chases schools in mid-water and strikes spoons, jigs and plugs.
Also called: cachorra-facão, peixe-cachorro, dourado-cachorro, chafalote, ripa, cachorrão, saranha
A relative of the cachorra (Hydrolycus), the cachorra-facão has a very long, thin body like a machete and a large upturned mouth with canine teeth. It preys on small fish, chasing them in mid-water and at the surface of large rivers, bays and reservoirs. It occurs from the Orinoco and the Amazon to the Plata basin, and is common in the Pantanal and the rivers of the Paraná. For sport anglers, it is the catch that shows up when working spoons and jigs for dorado: it jumps, shakes its head and cuts thin line with its teeth.
Elongated, compressed, silver body with a keeled belly. Large oblique mouth, turned upward, with canine teeth. Long pectoral fins and a very long anal fin; pectoral, pelvic and anal fins yellowish; dorsal and caudal fins translucent. The cachorra (Hydrolycus armatus) has a much taller body and enormous fangs; the dorado is golden and has differently shaped scales.
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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.
Amazon, Tocantins-Araguaia, Paraguay, Paraná and Uruguay basins: large rivers, Pantanal bays and reservoirs.
Habitat: Mid-water and surface of large rivers, bays, corixo mouths and reservoirs; follows schools of lambaris and sardines.
native to the basins
states
Amazonas, Pará, Amapá, Acre, Rondônia, Mato Grosso, Mato Grosso do Sul, Tocantins, Goiás, Minas Gerais, São Paulo, Paraná, Santa Catarina, Rio Grande do Sul
famous destinations
Good from March to May and August to October; at the peak of the cold, in the South and the Pantanal, it drops sharply.
Daytime, with peaks at dawn and dusk. Hunts by day, with peaks at dawn and in the late afternoon.
A cold front shuts down activity for one or two days.
Stable pressure helps; before a front there is often a peak.
Little effect.
Very muddy water hinders visual hunting.
A falling river concentrates the bait schools, with predators behind them.
Moderately sensitive.
Light chop helps surface fishing.
Mid-water, 0.5 to 4 m.
lures
natural baits
accessories
Fast retrieve and a tough leader: the fangs cut thin line.
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 national list (Portaria GM/MMA 1.667/2026).
In Goiás the cachorra-facão may only be killed between 35 and 50 cm, in the Araguaia-Tocantins and Paranaíba basins, and only for consumption on site.
Source: IN Semad-GO nº 17/2026, Annex I (in force May 28, 2026; on-site consumption only, zero transport)
Above 50 cm the cachorra-facão must be returned to the water in Goiás.
Source: IN Semad-GO nº 17/2026, Annex I (in force May 28, 2026; on-site consumption only, zero transport)
In Tocantins the cachorra-facão may only be kept at 40 cm or more. In TO anglers may not transport fish until Feb 28, 2029, except 1 native fish; they may consume up to 3 kg on site (Naturatins Ordinance 44/2026).
Source: Portaria Naturatins nº 47/2026, Annex I, as amended by Portaria nº 105/2026
Allowed: Recreational fishing only for non-native species and hybrids (peacock bass, tilapia, black bass, carp, croaker, etc.; piauçu remains prohibited), with handline, simple pole, or rod with spinning or baitcasting reel, up to 10 kg + 1 fish. In rivers, from shore only; in reservoirs, from a boat or from shore. Prohibited: floodplain lakes, aquatic-animal bait, within 1,500 m of dams and waterfalls, and within 500 m of confluences. Tournaments only in reservoirs and only with non-native species.
Source: IN IBAMA nº 25/2009
Allowed: Only exotic or hybrid species, 3 kg + 1 fish per day, with handline, rod, simple pole, or spinning or baitcasting reel. Nets prohibited. Keep the minimum distances from dams and reservoirs.
Source: Portarias IEF nº 154/2011 (São Francisco), 155/2011 (East) and 156/2011 (Grande/Paranaíba)
Allowed: Sport and guided fishing only in reservoirs, catch and release with barbless hooks (no keeping, transporting or eating). Subsistence: up to 5 kg per day, for household consumption only.
Allowed: Subsistence fishing by riverside residents and authorized scientific fishing. Decree 15.166/2019 (art. 11, §5) allows catch and release only in February and only in the channels of the Paraguay and Paraná rivers. For the rest of the period, not even catch and release is allowed. Check the Imasul portaria for each season.
Source: Decreto estadual MS nº 15.166/2019, art. 11; IN IBAMA nº 201/2008
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 fishing only in reservoirs, with handline, rod, or spinning or baitcasting reel. Fish may only be eaten on site, not transported. Competitions prohibited. Subsistence: 3 kg + 1 fish. State rules (GO and TO) may be stricter.
Allowed: Recreational fishing only in reservoirs, with on-site consumption. Subsistence: 5 kg + 1 fish. State rules may be stricter.
Allowed: In 2025/26: catch and release with barbless hooks and recreational fishing card; subsistence fishing on foot or from a rowboat, with simple pole or handline.
Source: Portaria Naturatins nº 244/2025 (2025/26 season); INIs MPA/MMA nº 12 and 13/2011
Allowed: Recreational fishing from shore, or from a boat without motor. Only handline or rod, line and hook, one gear per angler, up to 5 kg. Prohibited in floodplain lakes, within 1,500 m of dams, within 500 m of confluences, and in stretches listed in the rule (e.g., Turvo River).
Source: IN IBAMA nº 193/2008
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
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
Allowed: Subsistence fishing only.
Source: Portaria IBAMA nº 48/2007
Allowed: See the exceptions in Portaria 48/2007 and the state rules for each bank.
Source: Portaria IBAMA nº 48/2007
Use pliers and a boga: the teeth cut. Release quickly; the fish loses scales easily.
White meat with many fine bones; fried in thin steaks.
Length-weight relationship W = a·Lb (a = 0.00389, b = 3.15; 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.
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