Hypophthalmus marginatus
A mid-water catfish that filters plankton. The main fish caught in Tucuruí lake and the lower Tocantins. It does not take a hook.
Also called: mapará, mampará
Scaleless, long, laterally compressed catfish that lives in mid-water and surface schools in rivers, lakes and reservoirs. It filters zooplankton with long, fine gill rakers, so it does not chase bait. It rises to the surface at night, when it is caught with nets. It is the base of artisanal fishing in the Tucuruí reservoir and the lower Tocantins (Cametá), and an important export resource of Amazonas. There are three mapará species in the genus; Hypophthalmus marginatus is the most studied in fishing.
Elongated, compressed, silver body, scaleless. Eyes low on the side of the head, almost at mouth level. Wide mouth, no visible teeth, with long, flat barbels. Very long anal fin and small dorsal fin. Forked tail with a dark edge.
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Whitewater rivers, várzea lakes and large reservoirs of the Amazon and Tocantins-Araguaia; heavily fished at Tucuruí (PA) and the lower Tocantins.
Habitat: Mid-water and surface of lakes, reservoirs and whitewater river channels.
native to the basins
states
Amazonas, Pará, Amapá, Tocantins, Mato Grosso
Most fished in falling water and the dry season. From Nov 15 to Mar 15 there is a closed season in Amazonas, Acre, Pará and Amapá.
Nighttime. Rises to the surface at night after zooplankton; deeper by day.
Cold snaps reduce activity.
Little known effect.
Anglers report more catches on dark nights, when the school rises.
Little effect.
Falling water concentrates the school.
Not very sensitive.
Strong wind makes surface net fishing difficult.
Surface at night; down to 10 m by day.
A net fish of professional fishing. For amateur anglers it works as an indicator: where mapará is, peacock bass and pescada are hunting.
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 AM, AC, PA and AP the mapará (Hypophthalmus spp.) is in Annex II of the ordinance, with fishing prohibited from Nov 15 to Mar 15. Under art. 2 of the ordinance, anglers fishing with a handline or pole, line and hook are exempt from this ban, unless a stricter state rule applies; during the period the angler's limit is 5 kg + 1 fish.
In Tocantins the mapará may only be kept between 25 and 55 cm. The rule identifies the mapará as Hypophthalmus edentatus, a species of the same genus; in practice enforcement officers use the common name. 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
Above 55 cm the mapará must be returned to the water in Tocantins.
Source: Portaria Naturatins nº 47/2026, Annex I, as amended by Portaria nº 105/2026
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: 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: 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
Not applicable to hook fishing.
Fatty, tender meat, highly prized in Pará: grilled over coals, fried or moqueado (cooked over embers); also salted and smoked.
Length-weight relationship W = a·Lb (a = 0.0049, b = 3.09; 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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