Armored catfish from rocky bottoms of the Xingu River in Pará, with large white blotches. It is almost never caught on rod, but it turns up in the aquarium trade.
Armored catfish of the family Loricariidae, with a body covered in bony plates and a suckermouth used to scrape the bottom. It reaches 24 cm and can weigh up to 220 g. It lives in Brazil, in the Xingu River basin in Pará, on rocky bottoms with strong current. Adults hide under rock blocks, alone or in groups of three, in stretches down to 2 m deep. Juveniles hide in crevices between the rocks, together with other armored catfish. It feeds on algae and other items it scrapes from the rocks, mainly at night. It has no real value for rod fishing; its importance lies in the aquarium trade.
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 acari-bola-branca; in the meantime, see the similar species.
fun facts
Juveniles share hiding spots with other armored catfish, such as those of the genus Ancistrus.
how to recognize it
identification
Armored catfish with a flattened underside covered in bony plates and a rounded snout seen from above. Its strongest feature is the pattern of large white blotches on the dark body. It resembles Spectracanthicus murinus, which has small yellowish spots and a more pointed snout. The operculum, the gill cover, is bar-shaped with clearly visible denticles.
how acari-bola-branca 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.
Occurs in Brazil, in the Xingu River basin in the state of Pará, in rivers with strong current and rocky bottoms.
Habitat: Rocky bottom of fast-flowing rivers, with cover under boulders, down to 2 m deep.
native to the basins
Amazon
calendar and clock
when to fish
best time of day
Nighttime. Feeds actively at night, scraping algae and other items off the rocks.
what the law says
rules for the acari-bola-branca
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.
It does not bite or sting, but it has hard plates and denticles on the operculum, plus rigid spines on the fins, like other armored catfish. Hold it carefully with wet hands.
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.
