The cascudo-bicudo belongs to the family Loricariidae, the armored catfish: small, elongated and covered in bony plates, with a suckermouth on the underside. It reaches 9.7 cm. It is endemic to Brazil and known from the Tapajós River basin. It lives on the bottom of freshwater rivers, in tropical waters. The species belongs to the genus Spectracanthicus, of Amazonian armored catfish, and is known by the common name bicudo. Being so small, it is not big enough for sport fishing.
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 cascudo-bicudo.
how to recognize it
identification
Small armored catfish with an elongated body covered in bony plates and a suckermouth on the underside. It reaches 9.7 cm. Being endemic to Brazil, its restriction to the Tapajós basin is the best aid to identifying it: it does not exist outside it.
how cascudo-bicudo 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.
Endemic to Brazil, known from the Tapajós River basin.
Habitat: Bottom of tropical freshwater rivers.
native to the basins
Amazon
what the law says
rules for the cascudo-bicudo
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.
Not dangerous. It is small and has plates on the body: handle it carefully, holding it by the trunk, and return it to the water quickly.
calculator
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.01096, b = 3.03; 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.
