The macana knifefish belongs to the family Apteronotidae, the knifefishes with weak electric discharges, and reaches 38 cm, weighing up to 138 g. It lives in the Amazon basin and in rivers of Peru, in fresh water, from the bottom to midwater. Like other knifefishes, it has an elongated body, flattened from side to side, and a tapered tail. It rarely turns up on the line of rod anglers. In Peru the fish is called macana, and in Ecuador, anguila. It has commercial use and is kept in public aquariums.
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-faca-macana; in the meantime, see the similar species.
how to recognize it
identification
A very elongated body, flattened from side to side, with a long anal fin and no dorsal fin, typical of the knifefishes of the family. Reaches 38 cm. It looks like the itoui (Porotergus gymnotus), but that one reaches 85 cm. Both belong to the same family and occur in the Amazon basin.
how peixe-faca-macana 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.
Essential profile: the index uses a general fish model (weather, sun, moon and tide), without a season or time of day specific to this species.
Habitat: Rivers of the Amazon basin, from the bottom to midwater.
native to the basins
Amazon
what the law says
rules for the peixe-faca-macana
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.
A long-bodied fish with a weak electric discharge, with no danger to anglers. Remove the hook in the water and release it promptly.
calculator
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.00347, b = 3.06; 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.
