Paraguay

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 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.

The black ghost knifefish, Apteronotus albifrons, is a weakly electric knifefish from the upper half of South America, from Colombia to Paraguay. Usually sold at around 4 inches, it grows to 50 cm and needs a long-term housing plan. Its eyesight is very poor, and it navigates, finds prey and communicates using a weak electric field. In the wild it lives in swiftly flowing streams and rivers over sand.

The oscar, Astronotus ocellatus, is a large cichlid widely distributed in the Amazon region, recorded from Colombia and Venezuela south to Argentina. It grows to 350 mm SL and typically lives 10 to 20 years, both of which need taking into account before purchase. Most fish on sale come from commercial breeders in Eastern Europe or the Far East, in numerous ornamental strains, and genetic analyses suggest the genus contains additional, morphologically cryptic species.

The red-eye tetra, Bario sanctaefilomenae, is a characin from Brazil, Paraguay and Argentina, living mostly in clear rivers that feed the Pantanal. All fish in the trade are captive-bred in huge numbers and are unfussy about water chemistry and diet. Somewhat boisterous, it suits a community of active tankmates such as similarly sized tetras, rainbowfish and barbs, and can intimidate sedate species such as anabantoids or dwarf cichlids.

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 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.

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 flag cichlid, Mesonauta festivus, is a cichlid recorded from Venezuela, Peru, Brazil, Bolivia and Paraguay. It lives in well planted, slower-moving waters. Flag cichlids are found in most aquatic stores, but the fish usually sold under the name is M. insignis. It is peaceful, but becomes more aggressive when breeding.

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 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 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.

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.

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 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.