Described in 2005, it exists only in the Iguazu River basin above the Iguazu Falls, in Paraná, and is one of the largest native fish of that stretch. It lives in rapids and deep pools with rock bottoms, where the river still flows freely, and hunts fish. The dam series on the Iguazu turned much of the river into reservoirs and reduced this habitat. It is on the national list as Endangered (EN), which bans catching, transport, storage and sale; the IUCN also rates it Endangered. It is bred in captivity for research and conservation, and fish from licensed aquaculture are not covered by the ban. If you hook one by chance, release it right away, without taking it out of the water.
fun facts
The six living species of the genus Steindachneridion occur in Brazil, and all are on the national list of threatened species.
The species is bred in captivity, and there are studies on larval feeding for rearing and restocking.
how to recognize it
identification
Round, elongated body, broad, flattened head, large mouth and long barbels. Background colour very dark, almost black on the back (hence melanodermatum, 'dark skin'), with low-contrast dark spots. In the Iguazu above the falls there is no other large catfish with this shape; the jundiá is much smaller, with a shorter head and lighter colour.
how surubim-do-iguaçu fishing looks
Loading the next 7 days…
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.
Endemic to the Iguazu River above the falls, in Paraná, in the middle and lower Iguazu stretches, now largely dammed.
Habitat: Rapids and deep pools with rock bottoms, in the free-flowing stretches between dams.
native to the basins
Paraná
states
Paraná
calendar and clock
when to fish
best season
time of year
JanFebSeaAprMayJunJulAugSepOctNovDec
No season: catching banned. The weights only warn bottom anglers on the Iguazu that it may bite.
best time of day
Nighttime. Hunts at night; by day it stays in deep pools and among rocks.
weather, water and behavior
what affects the surubim-do-iguaçu
sensitivity The little bars show how much each factor affects this species. Five full: it feels it a lot.
cold and cold fronts
Cold reduces activity.
atmospheric pressure
Little known effect.
moon
Little known effect.
rain
Little effect.
water level
Depends on stretches with current, which are increasingly rare on the Iguazu.
noise
Moderate.
wind
Little effect.
depth
Bottom, in pools 3 to 15 m deep.
technique, gear and bait
how to fish
rod
not applicable: capture prohibited
spinning / baitcasting reel
not applicable
line
not applicable
leader
not applicable
hook
A circle hook without a barb helps release it unharmed if it bites by accident.
accessories
long-nose pliers for release
tip from an angler
Bottom fishing on the Iguazu with natural bait, it may bite. If the hook is deep, cut the line near the mouth and release the fish without taking it out of the water.
what the law says
rules for the surubim-do-iguaçu
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: Threatened species already listed before 2026: catching, transport and trade banned (Portaria GM/MMA nº 1.666/2026, art. 3º). Global IUCN assessment: Endangered (EN, 2018). Caught it by accident? Release it immediately.
Endangered species: catching it is prohibited
capture, transport, storage and trade prohibitedPRParaná
The Iguazu surubim is on the national list as Endangered (EN), and was already on the previous list. VU, EN and CR species have full protection: catching, transport, storage and trade are banned. Specimens from licensed aquaculture are not covered by the ban, and fish caught by accident must be released alive on the spot.
Other threatened freshwater fish (catching prohibited)
Freshwater species on the national list with catching prohibited that may take the sport angler's bait. Common curimbatá (Prochilodus lineatus) is NOT on the list.
piracema closures in the basins where the species lives
Spawning closure (piracema) in the Paraná River basin
01/11 to 28/02SPPRMGGOMSDF
Allowed: Recreational fishing only for non-native species and hybrids (peacock bass, tilapia, black bass, carp, croaker, etc.; piauçu remains prohibited), with handline, simple pole, or rod with spinning or baitcasting reel, up to 10 kg + 1 fish. In rivers, from shore only; in reservoirs, from a boat or from shore. Prohibited: floodplain lakes, aquatic-animal bait, within 1,500 m of dams and waterfalls, and within 500 m of confluences. Tournaments only in reservoirs and only with non-native species.
Spawning closure (piracema) in Minas Gerais (state rule)
01/11 to 28/02MG
Allowed: Only exotic or hybrid species, 3 kg + 1 fish per day, with handline, rod, simple pole, or spinning or baitcasting reel. Nets prohibited. Keep the minimum distances from dams and reservoirs.
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.
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.
Mandatory. Do not take it out of the water: cut the line close to the hook if it is deep and let the fish go.
in the kitchen
Not applicable: capture in the wild is prohibited.
calculator
how much it weighs without taking it out of the water
Length-weight relationship W = a·Lb (a = 0.00589, b = 3.1; FishBase). It's an average: a fat or lean fish can vary by 10% to 20%.
estimated weight
—
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 — Steindachneridion melanodermatum (ficha da espécie)Distribution, maximum size (53.2 cm standard length) and length-weight relationship (estimate for the group's body shape). The app's entry maximum weight was estimated with it. Page checked on Oct 13, 2026.
