The chambira (pirandirá), the smaller payara of the Amazon: silvery, with a huge mouth and two fangs that cross the snout. It strikes midwater baits in the current and jumps when hooked.
Also called: pirandirá, cachorra, peixe-cachorro, saranha-do-rabo-amarelo
The peixe-cachorro of the family Cynodontidae, a close relative of the payara (Hydrolycus armatus), but much smaller: FishBase and the genus revision indicate fish up to about 40 cm. It lives in central and upper Amazonia, in Brazil, Bolivia, Peru and Ecuador, and in Brazil the Tapajós River seems to mark the downstream limit. Adults prefer the channels of large rivers and tributaries, with white or black water, in stretches with current, where they hunt smaller fish with their long fangs. They spawn between November and April, after moving upriver. It shows up in peacock bass and payara fishing with spoons, jigs and midwater lures, and it fights with jumps. The names payara and pirandirá apply to both species, which confuses size and rule records.
fun facts
The two jaw fangs fit into holes in the snout when the mouth closes.
FishBase has an IGFA record of 117 cm and 17.8 kg under this scientific name, far above the species' known size; the identification of that fish is doubtful.
how to recognize it
identification
Elongated, compressed, silvery body with a large upturned mouth and two huge fangs on the lower jaw, which fit into holes in the snout when the mouth closes. Told apart from the payara (H. armatus) by its smaller size, the black spot at the base of the inner pectoral rays and a pelvic fin set higher on the flank. The chafalote (cachorra-facão) is much slimmer and longer, and the peixe-cachorro (Acestrorhynchus) lacks the fangs that cross the snout.
how vampire tetra 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.
Central and upper Amazonia: the Solimões-Amazonas channel and large tributaries such as the Madeira (with Guaporé and Mamoré), Purus and Tapajós, plus rivers of Peru, Bolivia and Ecuador. The Tapajós seems to be the downstream limit in Brazil.
Habitat: Channels of large rivers and tributaries, with white and black water, in stretches with current; rocky areas, current breaks and lake mouths. Juveniles stay in smaller tributaries and flooded forest.
native to the basins
Amazon
states
Amazonas, Pará, Acre, Rondônia, Mato Grosso
calendar and clock
when to fish
best season
time of yearbest: Aug–Nov
JanFebSeaAprMayJunJulAugSepOctNovDec
Low water and dry season (July to November): low river and fish concentrated in the channel and at lake mouths. In the flood it moves upriver to spawn and spreads out.
best time of day
Daytime, with peaks at dawn and dusk. Hunts by day, most active early and late in the afternoon, when it patrols the current breaks.
weather, water and behavior
what affects the vampire tetra
sensitivity The little bars show how much each factor affects this species. Five full: it feels it a lot.
cold and cold fronts
Cold snaps (friagem) shut down activity for a few days.
atmospheric pressure
Stable weather helps; a storm shuts fishing down for a few hours.
moon
Small effect.
rain
Rain at the start of the flood muddies the water and scatters the fish.
water level
Falling river: the best scenario, with fish on the channel's current breaks.
noise
Moderate: approach rocks and rapids slowly.
wind
Little effect in the channel; strong wind makes casting difficult.
spinning reel 2500 to 3000 or low-profile baitcasting reel 100
line
braid 20 to 30 lb
leader
fluorocarbon 40 to 50 lb or a 20 cm steel leader: the fangs cut thin line
hook
small treble hooks 2 to 1/0 on artificials; hook 1/0 to 3/0 for natural bait; the mouth is hard and bony
lures
spoon, 10 to 20 g
feather or hair jig, 1/4 oz
minnow and jerkbait, 7 to 10 cm
spinner #3 to 4
natural baits
live lambari
fish fillet
accessories
long-nose pliers
boga-grip
tip from an angler
Hard mouth: set the hook firmly and keep the line tight during jumps, or the lure will come loose.
what the law says
rules for the vampire tetra
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 of threatened species (Portaria GM/MMA nº 1.667/2026).
MT (Mato Grosso): the payara size can be enforced
60 cm (law cites only Hydrolycus armatus)MTAmazonconfirm with the agency
Annex II of Mato Grosso's fishing law sets 60 cm for the payara in the Amazon and Araguaia-Tocantins basins, but cites only Hydrolycus armatus. The pirandirá rarely exceeds 40 cm and, if enforcement does not separate the species, it would always be below the size. When in doubt, release.
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.
Use pliers and a gaff, away from the fangs. Remove the hook quickly, with the fish in or near the water, and release it in the current.
in the kitchen
White flesh full of bones, not highly valued in the market.
calculator
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.00661, b = 3.2; FishBase). It's an average: a fat or lean fish can vary by 10% to 20%.
estimated weight
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sources and references
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.
scientificFishBase — Hydrolycus scomberoides (ficha da espécie)Names, distribution, biology, length-weight relationship and country list. The entry cites a maximum length of 117 cm and 17.8 kg from the IGFA records base (2001) and, in the biology section, about 40 cm; we adopted the second value. The maximum weight in the app's entry was estimated from the length-weight relationship. The country list marks Colombia as a misidentification and Venezuela as doubtful. Page checked on 13/10/2026.
technicalSeriously Fish — Hydrolycus scomberoidesSummary of distribution, habitat, spawning season and the characters separating the species from other payaras, based on the revision by Toledo-Piza, Menezes and Santos (1999). Page checked on 13/10/2026.
