Parana basin

The marbled headstander, Abramites hypselonotus, is an anostomid from the Amazon, Orinoco and Paraguay-Paraná basins in South America. An ecological generalist, it occurs in turbid main river channels, minor tributaries and backwaters, and enters inundated zones during the annual floods. Best kept as a group in a large tank alongside cichlids, characins and catfishes, it may nip long or trailing fins and eat soft-leaved plants.

The Pantanal barracuda tetra, Acestrorhynchus pantaneiro, is a predatory acestrorhynchid from the Paraná, Uruguay and de la Plata basins. It also occurs in the rio Mamoré in Bolivia. A member of the A. lacustris group with a round humeral spot, it is virtually impossible to tell from its relatives in the trade unless collection data is known. It lives in open water, and a group must be of comparable size because acestrorhynchids are cannibalistic.

The manduba, Ageneiosus inermis, is a large auchenipterid catfish found throughout much of South America east of the Andes. At around 470 mm SL it would need an aquarium in excess of 400 x 120 cm as an adult and is largely unsuitable for private aquaria. An obligate carnivore, it can take surprisingly large prey, and the larger Ageneiosus species are often used as food fishes in their native countries.

The duck catfish, Ageneiosus ucayalensis, is an auchenipterid catfish described from Peru and recorded across the Amazon, Orinoco and Guianas. Body patterning apparently varies with locality, and fish from black water habitats, particularly on the Guiana Shield, tend to be darker. Growing to around 290 mm SL and capable of taking large prey, it is safe only with similarly sized catfishes or large pelagic characins, mostly a combination for public aquaria.

Ancistrus claro, the gold marble bristlenose catfish (LDA 008), is a suckermouth catfish from the rios Claro and Coxipó in Mato Grosso, Brazil. It inhabits flowing streams over boulders and bedrock. Sometimes confused with unidentified fishes such as A. sp. 'L352', it has long maxillary barbels and small spots on the head, with vermiform lines on the body in males and spots all over in females. A peaceful cave-spawner, it has been bred in aquaria on numerous occasions.

The bloodfin tetra, Aphyocharax anisitsi, is a characid endemic to the Paraná River drainage in Brazil, Paraguay and Argentina. A hardy species that adapts to a wide range of conditions, it can even be kept unheated in a well-insulated house, though it is less colourful in cooler water. Captive specimens over ten years old are not unheard of. It may nip long-finned or slow-moving tankmates, and the tank needs a tight cover as it will jump.

The dawn tetra, Aphyocharax nattereri, is a small characid from southern Brazil, Bolivia and Paraguay. In the hobby it is usually called A. paraguayensis, a name considered a synonym of A. nattereri since 2003. Confusion remains, because the type locality of A. nattereri lies on the main Amazon channel, far from most confirmed localities. It is most often imported as a contaminant among shipments of other species.

The green fire tetra, or Rathbun's bloodfin, Aphyocharax rathbuni, is a characid endemic to the Paraguay, Paraná and Uruguay river drainages. It is found in Brazil, Paraguay, Argentina and Uruguay, in streams and rivers shaded by floating or overhanging vegetation. Although suitable for a community aquarium, it has a reputation as a fin-nipper, and long-finned species such as many cichlids and anabantoids should be avoided as tankmates.

Borelli's dwarf cichlid, Apistogramma borellii, is from southern Brazil, Paraguay, Argentina and Uruguay. Also known as the umbrella or yellow dwarf cichlid, it occurs in creeks and tributaries of the rio Paraguay, lower rio Paraná and Uruguay systems. Captive-raised fish are the recommended choice for the community aquarium, while wild examples are best kept alone or with small dither fishes.

The Corumbá dwarf cichlid, Apistogramma commbrae, is widespread in the Paraguay River watershed of Argentina, Bolivia, Brazil and Paraguay. One of the smallest members of the genus, it is told apart with the rest of the A. commbrae complex by a conspicuous double caudal peduncle spot. Its habitats cool seasonally to as low as 16 °C, and it should be kept cooler over winter.

The three-striped apisto, Apistogramma trifasciata, is a dwarf cichlid from the Guaporé, Paraguay and middle Paraná basins. Found in Brazil, Paraguay and Argentina, it lives in sluggish creeks, tributaries and smaller rivers where leaf litter collects. A narrow third stripe from the pectoral-fin insertion to the anal fin helps separate it from congeners. The DATZ code is A204, with possibly conspecific forms from Argentina and the rio Guaporé coded A205 and A206.

Aspidoras taurus is a small armoured catfish known only from the upper Itiquira and Taquari rivers, in the rio Paraguay system of Mato Grosso, Brazil. Relatively common in the aquarium trade, it is sometimes mislabelled as A. menezesi, a valid but distinct species. Thick skin covering the infraorbitals, preopercle and reduced nuchal plate separates it from congeners.

The giant brochis, Brochis britskii, long known as Corydoras britskii, is an armoured catfish restricted to the upper rio Paraguay in Mato Grosso state, Brazil. It grows to around 90 mm SL and can be told from B. splendens and B. multiradiata, the other two species long kept in Brochis, by its 15 to 18 dorsal-fin rays. It forms aggregations in smaller tributaries and still waters such as backwaters, oxbows and marginal lakes.

The tail-spot pygmy cory, Gastrodermus hastatus, long known as Corydoras hastatus, is a tiny armoured catfish with a wide range across the Amazon and Río Paraguay basins. It is known from Brazil, Bolivia, Paraguay and northeastern Argentina. Unlike most congeners it swims in midwater, forming mixed schools with similarly patterned small characids such as Serrapinnus kriegi. It is frequently confused with G. pygmaeus, but has a dark, roughly diamond-shaped spot on the caudal peduncle where G. pygmaeus has a dark lateral stripe.

The pearl cichlid, Geophagus brasiliensis, comes from Atlantic-draining river systems of eastern and southern Brazil and Uruguay. It belongs to the 'G.' brasiliensis group, which still needs definitive classification. Colour and body shape vary with locality, and some coastal lagoon populations have evolved a degree of salt tolerance. Fish sold as Gymnogeophagus australis in Europe are more often this species, and non-native populations exist in several countries.

Hoplisoma gladysae, long known as Corydoras gladysae, is an armoured catfish known only from two localities in the Río Calchaquí watershed in Salta province, northwestern Argentina. The Calchaquí is a swift, snow-fed mountain river with hard water, and the species shows adaptations to life among rocks in flowing water, including a cryptic colour pattern, short fin spines and reduced body depth. It is unlikely to be collected for commercial purposes.

Hoplisoma petracinii, long known as Corydoras petracinii, is an armoured catfish known only from one ephemeral stream in the Río San Lorenzo watershed of Salta province, Argentina. It shows adaptations to life among rocks in flowing water, including a cryptic colour pattern, short dorsal and pectoral spines and reduced body depth. The stream runs almost dry for much of the year and is under great ecological pressure from the nearby city of Salta, road building and dumping of refuse.

The Buenos Aires tetra, Hyphessobrycon anisitsi, is a characid from the Paraná and Uruguay river systems in Brazil, Paraguay, Argentina and Uruguay. A popular and hardy aquarium fish, it is also available as a line-bred albino strain, sometimes traded as 'golden'. It has a reputation for fin-nipping, though mostly when too few are kept or space is limited, and a group of at least 8-10 is the minimum.

The flame tetra, Hyphessobrycon flammeus, is a small characid from Rio de Janeiro and São Paulo states in Brazil. Popular in the hobby, it is bred commercially in several countries and also sold as 'red', 'fire', 'rio' and 'Von Rio' tetra. In nature it is now uncommon or even extinct across much of its range, and the São Paulo populations may have been introduced by aquarists or breeders.

The black neon tetra, Hyphessobrycon herbertaxelrodi, is a characid from the upper rio Paraguai in Mato Grosso and Mato Grosso do Sul, Brazil. A ubiquitous aquarium fish since its discovery, it is produced commercially in several countries, so wild fish are no longer collected. It is widespread north and south of the Pantanal, favouring minor tributaries, headwater rivers, oxbows and seasonal floodplains.

Leporellus vittatus is an anostomid with a huge natural range across the Amazon, Paraná-Paraguay, São Francisco and Orinoco river systems. Unlike most anostomids it is adapted to a benthic existence in flowing water and spends most of its time on or around the substrate. Occasionally exported, it requires quite specialised conditions, an aquarium of at least 210 by 60 cm and ideally a group of six or more.

The serpae tetra, Megalamphodus eques, is a characid with an enormous range through much of the Amazon drainage and the Río Paraguay. Very common in the trade, it is also sold as the 'jewel', 'red minor', 'blood' or 'callistus' tetra, and ornamental strains include 'long-finned' and 'balloon' forms. It has a reputation for nipping the fins of tankmates, although this is most pronounced when too few are kept or space is limited.

The black phantom tetra, Megalamphodus megalopterus, is a characid from the upper rio Madeira and upper rio Paraguai in Bolivia and Brazil. Most records are from the rio Guaporé (Río Iténez in Bolivia). Popular in the hobby and bred commercially in several countries, it is also available as a 'long-finned' strain. Adult males have black fins with the pelvic, dorsal and anal enlarged, while females are deeper-bodied with reddish pelvic, anal and adipose fins.

The spotted metynnis, Metynnis maculatus, is a silver dollar probably confined to the upper rio Madeira and upper rio Paraguai in Bolivia and Brazil. It is most often confused with M. argenteus and M. lippincottianus, but it has more midlateral scales and more spines on the ventral keel than either. It schools in nature and needs a very large tank with a group of six or more.

The bronze cory, Osteogaster aenea, long known as Corydoras aeneus, is an armoured catfish described from Trinidad and accepted to occur across much of South America. That range looks more like a complex of similar, distinct species than a single one, and fish from outside Trinidad are of uncertain identity. Aquarium fish are almost all commercially farmed, and the names C. schultzei and C. venezuelanus are routinely misapplied to them.

Phenacogaster tegatus is a small characid from the upper rio Paraguay basin in Brazil and Paraguay and the Río Paraná in northeastern Argentina. It has been traded as 'six-eyed tetra', in reference to the two dark spots on each flank plus the eye. Peaceful but somewhat unsuitable for the general community aquarium, it is best kept in a group of at least 8-10 alongside similarly-sized characids and other small, non-predatory fishes.

The giant whiptail catfish, Pseudohemiodon laticeps, is a loricariid from the rios Uruguay, Paraná and Paraguay in Brazil, Paraguay and Argentina. Growing to 300 mm, it stays buried in soft substrate by day and emerges to feed at night, so a sandy substrate and very clean, stable water matter most. The male is a paternal 'lip brooder', carrying the eggs on his labial barbels for 12-14 days, and the species has been bred in aquaria.

The red bellied piranha, Pygocentrus nattereri, occurs through much of the Amazon basin and south into the Paraná and Uruguay river systems. Famed as a rapacious predator, it is among the most notorious freshwater fishes in the world. According to Herbert Axelrod (1976), the myth began with a feeding frenzy staged for Theodore Roosevelt in Brazil in 1913. Usually only juveniles form aggregations, and the species is relatively easy to breed in the aquarium.

The Pantanal eartheater, Satanoperca pappaterra, is a cichlid from the rio Guaporé and upper rio Paraguai basins in Brazil, Bolivia and Paraguay. Relatively rare in the ornamental trade and much sought after, it is easily told from all known congeners by a series of prominent black blotches beneath the dorsal-fin and a well-defined dark band along the side of the body. It has been introduced to the upper rio Paraná in southeastern Brazil.

The banded 'cory', Scleromystax barbatus, is an armoured catfish from coastal rivers in south-east Brazil, between Rio de Janeiro and Santa Catarina. At 90-100 mm it is the largest of the Corydoradinae, and it was formerly included in Corydoras. The hobby also knows it as 'bearded cory', 'checkerboard cory' and 'filigree cory'. Males are aggressively territorial towards one another and cannot be kept together in smaller aquaria.

The sailfin 'cory', Scleromystax macropterus, is an armoured catfish from coastal rivers of southern Brazil and the rio Paraná basin in Paraguay. Most have been collected from small blackwater streams draining directly into the Atlantic, but it also inhabits roadside ditches. Males are somewhat territorial towards one another and should not be kept together in smaller aquaria, and its stiffened pectoral-fin spines can give a painful 'sting'.

The white piranha, Serrasalmus brandtii, may be restricted to the rio São Francisco watershed in eastern Brazil. Also known as 'green piranha' or 'Brandt's pirambeba', it appears infrequently in the trade, and its name is sometimes misapplied to the distantly related Pygopristis denticulata. Adults are uniformly golden-bronze with dark fin margins and a concave head profile above the eye. It is best kept alone as a single specimen.

The spotfin hatchetfish, Thoracocharax stellatus, is the most widespread neotropical hatchetfish, recorded from much of South America. It is told from its only congener, T. securis, by a prominent dark spot in the dorsal fin, and is sometimes traded as 'platinum hatchetfish'. It feeds almost entirely on insects, and a tightly fitting cover is needed because it can clear several metres in one jump.

Corydoras aurofrenatus is an armoured catfish from the Río Paraguay-Paraná system in Paraguay, also recorded in Argentina and Bolivia. It has been traded as C. sp. 'Corrientes' and CW005. Each flank carries two dark blotches, one behind the head and one below the adipose fin, and the caudal-fin lobes are long with the upper more extended. C. ellisae has been treated as a junior synonym, although this appears not to have achieved wide acceptance.

Hoplisoma carlae, long known as Corydoras carlae, is an armoured catfish endemic to the lower Río Iguazu in Misiones province, northern Argentina. It appears restricted to small tributaries above the Iguazu Falls with clear, fast-flowing, shallow water, and needs stable, clean conditions. Two large, indistinct dark blotches on each flank separate it from most similar congeners, and it was introduced to the hobby by Hans-Georg Evers in 2010.

Hoplisoma ehrhardti, long known as Corydoras ehrhardti, is an armoured catfish from eastern Brazil, known from southern São Paulo to northern Santa Catarina states. It inhabits minor rivers and small streams with soft substrates, a number of them modified by human activity. It is rarely traded and resembles several congeners, including H. carlae, H. paleatum and H. steindachneri.

Hoplisoma flaveolum, long known as Corydoras flaveolus, is an armoured catfish from tributaries of the rio Tietê in the upper rio Paraná basin, São Paulo state, Brazil. It is exceptionally rare in the hobby. Its closest congener is H. lacrimostigmata, from which it differs in having more serrations on the pectoral- and dorsal-fin spines, a rounded snout and flanks and fins densely patterned with spots and bars.

Hoplisoma lacrimostigmata, long known as Corydoras lacrimostigmata, is a small armoured catfish known only from the rio Ivaí basin, in the rio Paraná drainage of Paraná state, southern Brazil. It has three nasal pores and four to six small, rounded black blotches along the centre of the flank. It is most similar to H. flaveolum, but has fewer serrations on the pectoral- and dorsal-fin spines, a slightly pointed snout and a more slender body.

The yellow tetra, Hyphessobrycon bifasciatus, is a characid from coastal rivers of southeastern Brazil between Espírito Santo and Rio Grande do Sul. It also occurs in parts of the upper Paraná basin, in floodplain tributaries, lakes and streams, usually under forest cover. Two vertically elongate humeral spots, the front one more prominent, help separate it from similar congeners. Generally peaceful, it is best kept as a group of 8-10 or more.

The redbreast acara, Laetacara dorsigera, is a small cichlid from the Guaporé in Bolivia and Brazil, and the Paraná and Uruguay systems further south. Breeding males and females develop conspicuous red cheeks, opercula and belly, a feature L. curviceps lacks. A dark spot in the middle of the dorsal fin is shared only with L. curviceps and L. flamannellus. Populations vary in colour pattern, and it is a biparental substrate spawner growing to around 37 mm SL.

L113, Megalancistrus parananus, is a large suckermouth catfish from the rios Paraná, Paraguay and Uruguay in Brazil, Paraguay, Uruguay and Argentina. It was formerly thought to include L234, but only L113 appears native to these drainages, while L234 comes from the rio São Francisco. The largest recorded specimen measured 588 mm, and it can behave very aggressively in confined surroundings.

L234, the dragon hi fin pleco, is a large Megalancistrus catfish known only from the rio São Francisco system in eastern Brazil. The L-number was previously applied to Megalancistrus parananus, but that species is native to the Paraná, Paraguay and Uruguay drainages, so L234 appears to be an unidentified species. It grows to 500 to 600 mm and can behave very aggressively in confined surroundings.

The dusky millions fish, Phalloceros caudimaculatus, is a small livebearer native to Brazil, Paraguay, Uruguay and Argentina. Feral populations in Australia, New Zealand, Ethiopia and Malawi were purportedly introduced for mosquito control and are now considered invasive. Highly variable in colour pattern, it is known in the hobby in spotted and golden ornamental forms. P. caudimaculatus is the type species of a genus that was monotypic until 21 new species were described in 2008.

The piraya, Pygocentrus piraya, is a piranha restricted to the rio São Francisco watershed in eastern Brazil. It can be identified by bright yellow-orange pigmentation on the lower jaw, opercle and flanks in life, and larger specimens have rays in the adipose fin. It is best maintained alone because mature individuals are reported to be extremely aggressive towards one another when space is limited.

The biara, Rhaphiodon vulpinus, is a dogtooth characin found from the Orinoco and Amazon basins south to the Río de la Plata in Argentina. The only member of its genus, it grows to 600 to 800 mm and is an obligate piscivore, and it is suitable only for public installations or the very largest private aquaria. Juveniles are seen for sale quite regularly, most often without adequate information on their long-term care.

Scleromystax prionotos is an armoured catfish known only from coastal rivers in Minas Gerais, Espírito Santo, Rio de Janeiro and São Paulo, Brazil. Like its congeners it is a facultative air breather and occasionally rises to gulp air at the surface. Its stiffened pectoral-fin spines can pierce human skin, so care is needed when handling it.

Hyphessobrycon auca is a small characid known only from two ponds in the Esteros del Iberá wetlands of Corrientes province, northern Argentina. The ponds lie on a sand bar deposited by the Paraná during the Pleistocene and hold soft, mildly acidic, rain-fed water. It looks very similar to H. anisitsi and is told apart by its dentition and by the small hooks on the fins of males.

Hyphessobrycon balbus is a small characid known only from upper Paraná basin headwaters in the Federal District and Goiás, central Brazil. Most records come from the rio São Bartolomeu, including the Bananal, Santa Maria-Torto and Gama tributary systems.