Amazon

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 polka dot lyre tail pleco, Acanthicus adonis, is a very large loricariid catfish from the rio Tocantins in Brazil. Thought to range across much of the Amazon basin, it is traded as spotted juveniles in quite large numbers despite its patent unsuitability for aquaria. It reaches 600 mm or more, loses its spotted patterning as it matures and becomes increasingly belligerent with age, so it can only be recommended to owners of the largest private aquaria or tropical ponds.

The lyre tail pleco, Acanthicus hystrix, is a very large loricariid catfish from the Amazon region of Brazil and Peru. A handful of records come from the Orinoco in Venezuela. Juveniles are traded in quite large numbers, but it can reach at least 1000 mm in nature and 500 to 600 mm in captivity, and becomes increasingly belligerent with age. Young fish are easily told from A. adonis by lacking its white to yellowish body spots.

The chocolate talking catfish, Acanthodoras cataphractus, is a doradid catfish from the northern Amazon basin and Atlantic drainages of the Guianas. It is most often exported as bycatch among Platydoras armatulus and is sold under the same trade names as A. spinosissimus, which has pale blotches on the back between the dorsal and caudal fins where this species has pale lines or no markings. Largely nocturnal and gregarious, it is best kept in a group of at least four.

The chocolate talking catfish, Acanthodoras spinosissimus, is a doradid catfish from the northern Amazon basin and the Essequibo in Guyana. Usually exported as bycatch among Platydoras armatulus, it is sold under the same trade names as A. cataphractus, and the most useful difference is the pale blotches on its back between the dorsal and caudal fins. Largely nocturnal and gregarious, it is best kept in a group of at least four.

The red barracuda tetra, Acestrorhynchus altus, is a predatory acestrorhynchid that may be restricted to the lower Amazon in Brazil. A member of the A. lacustris group, it has a round humeral spot and is virtually impossible to tell from its relatives in the trade unless collection data is known. An obligate piscivore of open water, it is best kept in a group of four or more of comparable size, since acestrorhynchids are cannibalistic.

The red-tailed freshwater barracuda, Acestrorhynchus falcatus, is a predatory acestrorhynchid from the northern Amazon and Orinoco basins. It also occurs in coastal rivers of Guyana, Suriname and French Guiana. Its large humeral spot, shaped like an inverted tear drop, separates it from other Acestrorhynchus. Reaching 250 to 275 mm, it needs plenty of open water, and a group must be of comparable size because acestrorhynchids are cannibalistic.

The big-eyed cachorro, Acestrorhynchus falcirostris, is a large predatory acestrorhynchid from northern Amazon drainages and the Orinoco. The two dark body stripes of the A. nasutus group appear only in its juveniles, and at 320 to 350 mm SL it grows far larger than the other members. A black fringe to the rear of the operculum gives it a 'collared' look. It needs open water, and a group must be of comparable size because acestrorhynchids are cannibalistic.

The striped barracuda tetra, Acestrorhynchus isalineae, is a small predatory acestrorhynchid from the rio Madeira basin in the Brazilian Amazon. Most records come from the type locality, a tributary of the rio dos Marmelos. Like others in the A. nasutus group it keeps two dark longitudinal stripes into adulthood and stays around 100 mm. Acestrorhynchids are cannibalistic given the opportunity, so a group must be of comparable size.

The pike tetra, Acestrorhynchus microlepis, is a predatory acestrorhynchid from northern Amazon drainages and the Orinoco. It also occurs in coastal rivers of Guyana, Suriname and French Guiana. A member of the A. microlepis group, it has a small blackish spot behind the gill cover and is separable from the very similar A. grandoculis only by counts. It tends to take smaller prey such as tetras, and acestrorhynchids are cannibalistic, so a group must be of comparable size.

The sheep pacu, Acnodon normani, is a serrasalmid from Brazil, possibly restricted to the Xingu and Tocantins watersheds of the Amazon basin. Also known in the trade as 'tiger pacu', it is often said to be a frugivore or herbivore, but aquarium observations suggest it also feeds on the scales of other fishes. That makes it unsuitable for the community aquarium, although it does not seem to target much smaller species.

The spotted talking catfish, Agamyxis pectinifrons, is a doradid catfish from the Amazon basin in Bolivia, Brazil, Colombia and Peru. Very common in the trade, it is hardy and relatively long-lived, and recommended to beginners and experienced aquarists alike despite its adult size. It closely resembles A. albomaculatus, known only from the Río Orinoco drainage in Venezuela, and the two are probably sold under the same trade names.

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 bottlenose catfish, Ageneiosus marmoratus, is a predatory auchenipterid catfish from Guyana, Suriname and the upper Amazon in Peru and Ecuador. Also sold as 'Guyana slopehead', 'dolphin' or 'hammerhead' catfish, it loses much of its black-blotched juvenile patterning as it grows. Surprisingly peaceful with anything too large to swallow, it is active and sometimes skittish, and needs a tank of at least 150 x 60 cm.

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.

The marbled talking catfish, Amblydoras nauticus, is a small doradid catfish from Peru, described from Nauta in the Peruvian Amazon. It is often still sold as A. hancockii, a name now considered a synonym of Platydoras hancockii. Hardy and tolerant of a wide range of water conditions, it is secretive and rarely seen by day. It makes audible sounds by grinding its pectoral spines in their sockets and by resonating the swim bladder, and its spines tangle easily in nets.

Ancistrus dolichopterus, the starlight ancistrus (L183), is a bristlenose catfish most likely endemic to the middle and lower rio Negro, Brazil. It inhabits blackwater streams. The name has been used for the common bristlenose and other similar species, while this fish has been called A. hoplogenys, and much of the literature confuses them. It differs from all congeners in having 9 soft dorsal-fin rays, and is territorial with conspecifics and similarly-shaped species.

The striped headstander, Anostomus anostomus, is an anostomid from the Amazon and Orinoco river systems in Peru, Brazil, Venezuela and Guyana. It lives along rocky shores of fast-flowing rivers, grazing algae and small invertebrates from the rocks. Although it shoals in nature, it is very quarrelsome with conspecifics when only a few are kept, so it is best kept singly or in a group of 6 or more in a larger tank.

Apistogramma agassizii is a dwarf cichlid found through much of the Amazon/Solimões basin, from the Río Ucayali in Peru to the Capim River in Brazil. Colour and pattern vary considerably with locality, and numerous ornamental forms have been selectively bred for the trade. It inhabits slower-moving tributaries and creeks where leaf litter collects. Captive-raised fish suit the community aquarium, while wild fish are best kept alone or with small dither fishes.

The redspot dwarf cichlid, Apistogramma alacrina, is from the Río Guaviare (Orinoco) and Río Orteguaza (Amazon) drainages in Colombia. It differs from all other described members of the genus in having dark blotches at the dorsal and ventral base of the pectoral fins. Three very similar fishes coded A106, A107 and A108 may or may not be conspecific with it, since they show some differences in colour pattern and morphology.

The Inca dwarf cichlid, Apistogramma baenschi, is from tributaries of the lower Río Huallaga in the Amazonian portion of northern Peru. Coded A188 under the DATZ system, it is produced on a commercial basis and is perhaps among the most suitable Apistogramma for those new to dwarf cichlids. Wild fish come from shallow forest tributaries with very soft, tea-stained water and a pH measured between 4.1 and 6.3.

The two-striped dwarf cichlid, Apistogramma bitaeniata, ranges across the Peruvian, Colombian and Brazilian Amazon, from the Marañón to the Tapajós. Also known as the banded dwarf cichlid, it occurs in several colour forms depending on locality, loosely grouped as 'red', 'blue', 'orange' and 'yellow' in the hobby. Many locality names are in use for these forms, and several are regularly applied incorrectly.

Apistogramma brevis is a dwarf cichlid from the Rio Uaupés basin in far northwestern Brazil and the Rio Tiquié in southern Colombia. It has also been recorded in the upper Rio Negro and Rio Orinoco, and inhabits slow-moving blackwater streams where the pH can drop as low as 4.0 or 5.0. Coded A168, it is the type species of the A. brevis group, and breeding is not too difficult if very soft, acidic water can be provided.

The cockatoo cichlid, Apistogramma cacatuoides, is a small cichlid from the upper Amazon basin, from the Ucayali in Peru to the Solimões in Brazil. It lives in slow tributaries, backwaters and creeks where leaf litter collects. Numerous line-bred forms such as 'double red' and 'orange flash' are traded, and captive-raised fish suit a community aquarium, while wild fish 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.

Apistogramma eunotus is a dwarf cichlid from the Río Ucayali in Peru and the Solimões/Amazon in Colombia and Brazil, as far east as the Japurá. Coded A73 under the DATZ system, it has similar-looking, possibly conspecific populations referred to as A74 to A77 depending on locality. It inhabits slow-moving streams, creeks and tributaries, and captive-raised fish are the recommended choice for the community aquarium.

Apistogramma norberti is a dwarf cichlid from the Río Tahuayo and Río Tamshiyacu, minor Amazon tributaries south of Iquitos in northeastern Peru. Known before its description as A. sp. 'großmaul' or 'bigmouth', and coded A190, its position within the genus is unresolved and it is only tentatively placed in the A. cacatuoides group. It lives in minor jungle streams whose volume changes significantly with the season.

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 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 two spot astyanax, Astyanax bimaculatus, is a characid ranging from Panama through most of the Amazon and Orinoco basins. It lives in a wide variety of biotopes, from swiftly-flowing rivers and streams to ponds, ditches and reservoirs. The name is currently applied to what is considered a species complex of at least four taxa, and aquarium fish most often arrive as contaminants among shipments of other species.

Kennedy's tetra, Astyanax kennedyi, is a small characid endemic to the upper Amazon basin in Peru, around the city of Iquitos. Like most Astyanax it is rarely offered for sale, and the occasional specimen turns up mixed among shipments of wild fishes from Peru.

The midnight catfish, Auchenipterichthys coracoideus, is an auchenipterid catfish from the Peruvian and Brazilian Amazon and the Essequibo drainage. Also known as the 'Zamora woodcat', it has often been misidentified as A. thoracatus, and the two differ principally in anal-fin ray count. By day it shelters among submerged roots, tree stumps or vegetation in turbid rivers and flooded areas, emerging to feed in open water at night.

Axelrodia stigmatias is a tiny characid from the western Amazon region in Brazil and Peru, sometimes traded as the 'white star' or 'pepper' tetra. It resembles A. riesei but has a more elongate body and is silvery yellow in life where that species is red. It is said to inhabit blackwater environments, and given its small size and somewhat specialised requirements it is best kept alone or with diminutive, non-aggressive characids and small catfishes.

The cupid cichlid, Biotodoma cupido, is a geophagine cichlid from much of the Amazon basin, north to the Essequibo in Guyana and south to Bolivia. Also traded as the 'green-streaked eartheater', it varies in colour pattern and shape by locality, and most traded fish come from around Santarém in Pará state. Unless breeding it is surprisingly peaceful. Its relatively compact body and a dark flank blotch above the upper lateral line separate it from B. wavrini.

Biotoecus opercularis is a small geophagine cichlid from the middle Amazon basin in Brazil, including the lower Madeira, Tapajós and Negro. It favours shallow, slow-flowing water over sand with leaf litter and submerged wood, often stained with tannins. Several populations are traded, among them B. sp. 'rio Negro' from the rio Jauaperi and B. sp. 'Santarém' or 'Tapajós', though no scientific evidence shows them to be more than one species. It should not be mixed with other Biotoecus species or populations.

Boulengerella maculata is a pelagic ctenoluciid found throughout much of the Amazon, Orinoco and Tocantins river systems. Colour pattern varies considerably, with some specimens much paler than others, and this may be correlated with water type. Random dark spots on the upper body, and a dark stripe only behind the eye when one is present, separate it from the similar B. lateristriga. It reaches 329 mm SL and needs an aquarium with base dimensions of 240 by 90 cm or more.

The zebra shovelnose, Brachyplatystoma tigrinum, is a pimelodid catfish from the upper Amazon basin in Brazil, Colombia and Peru. Adults appear to be obligate inhabitants of main river channels with strong flow, often around cataracts and rapids, and most aquarium fish are juveniles collected around Iquitos in Peru. It is sometimes confused with B. juruense, especially when young, but has a more well-defined colour pattern, a slenderer body and longer barbels.

Brachyrhamdia meesi is a small heptapterid catfish described from near Belém, at the mouth of the Amazon in Brazil. Its precise distribution is unclear, with one record from the Río Madre de Dios basin in Peru. Rare in the hobby, it is normally imported as bycatch among other fishes, particularly Otocinclus, and juveniles may mimic Otocinclus or smaller Corydoras. A dark vertical bar through the eye separates it from the similar B. marthae.

Brochis gomezi, long known as Corydoras gomezi, is an armoured catfish from the western Amazon basin in Colombia and Peru, including the 'Tres Fronteras' region. Collection records are scarce and its range is unclear. It resembles B. leopardus, B. orphnopterus, C018 and C131, but has separate, distinct spots on the upper body, six bands on the caudal fin and a relatively slender body.

The mosaic cory, Brochis haraldschultzi, long known as Corydoras haraldschultzi, is an armoured catfish endemic to the rio Guaporé (Río Iténez) in northeastern Bolivia and western Brazil. It resembles Hoplisoma sterbai but has a more extended snout and grows larger, to 85 mm SL. Its head carries dark vermiculations and spots on a light background, where H. sterbai has light markings on dark. The type locality was once modified to the rio Tocantins, well over 1000 km away, but the original Guaporé locality appears to be correct.

The imitator cory, Brochis imitator, long known as Corydoras imitator, is an armoured catfish endemic to the upper rio Negro basin in northern Brazil and southern Venezuela. It is one of several rio Negro congeners with an oblique dark bar along the dorsal surface of the body, a group that includes Hoplisoma adolfoi, H. burgessi and H. duplicareum. It inhabits pristine blackwater tributaries and flooded forest with tea-coloured water, very little hardness and a pH of 4.0-6.0.

Brochis incolicana (C001), long known as Corydoras incolicana, is an armoured catfish from the rio Içana in the upper rio Negro basin, northern Brazil. It presumably also occurs in eastern Colombia, where the Içana forms the border. The first fish to receive a 'C' number, in 1993, it was described the same year in a hobbyist magazine and is difficult to identify accurately. The colour pattern is said to be extremely variable, but the dark bar through the eye and the dark marking at the dorsal-fin base are apparently consistent.

Brochis lamberti (C009), long known as Corydoras lamberti, is an armoured catfish known only from the lower Río Pastaza, a tributary of the Río Marañón in Loreto, northern Peru. Similar-looking fish are known from tributaries close to Iquitos, and it is unclear whether these, 'C009' and B. lamberti are the same species. It is rare in the hobby and difficult to identify without collection details, so it may have been traded under other names.

The leopard cory, Brochis leopardus, long known as Corydoras leopardus, is a spotted armoured catfish from the western Amazon basin in Peru, Ecuador, Bolivia and Brazil. It looks very like Hoplisoma julii and H. trilineatum, but has a longer, more pointed snout and grows larger. Dias et al. (2024) moved it to the genus Brochis and put the two lookalikes in Hoplisoma, so the resemblance does not reflect a close relationship. The type specimens were aquarium imports.

Known in the hobby as the hognose 'Brochis', Brochis multiradiata, long known as Corydoras multiradiatus, is an armoured catfish from the northwestern Amazon basin in Ecuador and Peru. Formerly placed in Brochis, it has an extended snout and 17-18 dorsal-fin rays, against 6-8 in other Corydoras. Little is known of its habitat, but it is likely to live in smaller tributaries and still waters such as backwaters and oxbows, as closely related species do.

The reticulated cory, Brochis reticulata, long known as Corydoras reticulatus, is an armoured catfish from the lower Amazon basin in Brazil, also known as the network cory. One of the commoner species seen in dealers' tanks, it is a good cory for the beginner. Very peaceful, it should be kept in a group of at least six, and like other corys it is sensitive to dirty substrates.

The false network cory, Brochis sodalis, long known as Corydoras sodalis, is an armoured catfish from the upper Amazon in Loreto, Peru, and Amazonas state, Brazil. It inhabits small tributaries, creeks, pools and areas of flooded forest. Very peaceful, it is best kept in a group of at least six, and it can be spawned in a similar way to other Corydoras.

The emerald 'brochis', Brochis splendens, long known as Corydoras splendens, is an armoured catfish recorded throughout much of the Amazon basin in Brazil, Peru, Ecuador and Colombia. It is sometimes called the 'common brochis', and juveniles are sometimes traded as 'hi-fin cory' for their enlarged dorsal fin. Its 10 to 12 dorsal-fin rays separate it from B. britskii and B. multiradiata, the other two species long kept in Brochis, and certain populations are thought likely to represent distinct species.

The red-tailed brycon, Brycon cephalus, is a large characid from the upper Amazon basin in Peru, Bolivia and Brazil, known in Brazil as the matrinxã. It migrates twice a year over large distances between nutrient-poor tributaries and silt-laden white water rivers, where it spawns. B. rubricauda and B. orbignyanus resemble it closely. An active, pelagic shoaling fish with sharp teeth, it grows to 220 mm SL and needs a very large, well-covered tank as it jumps.

The blackwing hatchetfish, Carnegiella marthae, is a small freshwater hatchetfish from the upper Orinoco in Venezuela and the rio Negro in Brazil. It appears to be a stenotypic inhabitant of blackwater, found in igapó and igarapé habitats with overhanging vegetation and leaf litter. Very peaceful but small and timid, it is best kept in a group of 10 or more with similarly sized, peaceful fishes.

The pygmy hatchetfish, Carnegiella myersi, is a tiny freshwater hatchetfish from the Peruvian Amazon basin, with a second population in Bolivia. The smallest and most delicate of the nominal hatchetfishes, it has a shallower, rounded keel that gives it an elongate profile. It lives in small, shaded, shallow forest streams and must be kept in a group of at least six, away from active tankmates.

The marbled hatchetfish, Carnegiella strigata, is a hatchetfish from the Amazon and Orinoco basins and coastal rivers of Guyana and Suriname. Popular in the hobby, it is collected for the trade mostly in the rio Negro basin in Brazil. Its larger size and dark, marbled pattern set it apart from congeners, though the pattern varies and the wide range may be open to question. It appears to live only in blackwater.

The reticulated driftwood catfish, Centromochlus reticulatus, is a small auchenipterid first known from the upper Rupununi River basin in Guyana. Its secretive, mostly nocturnal habits mean it may have been overlooked elsewhere, and it has been recorded from the rio Preto da Eva near Manaus, Brazil. Sometimes traded as 'purple oil catfish', it is highly gregarious and ideally kept in groups of at least eight.

The blue whale catfish, Cetopsis coecutiens, is a cetopsid catfish from the Amazon, Tocantins and Orinoco river basins. In the wild it swims in voracious feeding groups, homing in on weakened fish by smell and burrowing into prey. It will bite chunks out of tankmates much bigger than itself, so it is best kept alone, and at up to 26.5 cm it needs a large tank with strong water flow and dim lighting.

The tucanfish, Chalceus erythrurus, is a large characin from parts of the Amazon basin in Peru and Brazil. It lives in the surface waters of floodplain rivers and lakes. The red or yellow caudal fin separates it from the pink-tailed C. macrolepidotus. Fast and a renowned jumper, it needs a lot of swimming space and a well-fitting cover, and it does best singly or in a group of more than six.

The spotted headstander, Chilodus punctatus, is a headstander from much of the Amazon, the western Orinoco and coastal rivers of Guyana and Suriname. Also called the 'checkered headstander', it lives in slow-moving rivers, oxbows and floodplain lakes, and its colour pattern appears to vary with locality. Shy and peaceful, it is sensitive to dissolved organic wastes and should never be introduced to a biologically-immature aquarium.

The Amazon puffer, Colomesus asellus, is a freshwater puffer found throughout much of the Amazon basin, with records north to Guyana and Venezuela. Also traded as the South American puffer or 'SAP', it is told from congeners by a transverse row of dermal flaps across the chin. It lives mostly in well-oxygenated river habitats, is intolerant of organic waste, and forms loose aggregations, so a group of 6 or more is best, away from the general community.

The banded puffer, Colomesus psittacus, is a large puffer of coastal waters from Colombia and Venezuela through the Guianas to northeastern Brazil. It also occurs in Trinidad and Tobago and the Caribbean islands, and inhabits mangrove swamps, estuaries and the lower reaches of rivers. Growing to 290 mm SL, it is the largest of its genus and has six dark bands across the back. Likely to prove aggressive in all but the largest systems, it is not a popular aquarium fish.

The red-spotted tetra, Copeina guttata, is a lebiasinid from the middle and upper Amazon basin in Brazil, Peru, Ecuador and Colombia. Reaching 76 mm, it needs a tank of at least 120 x 30 cm. The eggs are apparently deposited in a shallow depression dug in the substrate and guarded by the male. Like many fishes from pristine environments it is intolerant of organic pollutants and requires spotless water.

The splash tetra, Copella arnoldi, is a lebiasinid from the lower Amazon basin in Brazil and coastal drainages of Guyana, Suriname and French Guiana. It spawns out of the water: a pair leap together onto overhanging vegetation and cling there while the eggs are laid. Zarske (2011) treats the Guianas populations as C. carsevennensis, restricting C. arnoldi sensu stricto to the lower Amazon, though Mol (2012) considers the two synonymous.

Copella callolepis is a small lebiasinid from the central Amazon region of Brazil, where all recent records come from. It is quite common in the aquarium trade but normally misidentified as C. nattereri or the very similar C. meinkeni. It lacks the dark lateral stripe of C. nattereri, and differs from C. meinkeni in a black triangular marking in the lower caudal-fin lobe and blue-black to dark brownish-red spots.

The spotted splashing tetra, Copella meinkeni, is a small lebiasinid from the central Amazon region, with most records from the rio Negro and Orinoco. It has been widely referred to as C. nattereri in aquarium literature, but lacks that species' dark lateral stripe and has 5-6 rows of bright red spots on the body. The similar C. callolepis is also traded. It inhabits forest streams with tea-coloured water and lays its eggs among vegetation.

Copella nattereri is a small lebiasinid widespread in the middle and upper Amazon drainage in Peru and Brazil. It is sometimes traded as C. sp. 'red line', 'spotted tetra' or C. nigrofasciata, and its name was long applied to C. callolepis and C. meinkeni. Of the three it alone has a dark lateral stripe, and it has no more than three rows of red spots on the flanks. It inhabits forest streams and flooded forest.

Fowler's cory, Corydoras fowleri, is a long-snouted armoured catfish from the Amazon basin in Peru. Also known as the 'huanta cory' and 'milegros cory', it is often confused with C. coriatae and C. semiaquilus, and aquarium fish are regularly misidentified. Most long-snouted cories grow larger and are more aggressive than other Corydoras, and this one is suitable only for larger community aquaria.

The Peru black cory, Corydoras semiaquilis, is a long-nosed armoured catfish from the western Amazon basin in Peru and Brazil. A few colour forms are available in the trade, sometimes under invalid names such as C. 'huanta' or C. 'milagros'. Males can be somewhat aggressive towards one another, although with sufficient space no real damage should occur, and a group of at least six is best.

The sailfin characin, Crenuchus spilurus, is a crenuchid from much of the Amazon and Orinoco drainages and coastal rivers of the Guianas. The only described member of its genus, it varies considerably in colour pattern and morphology across that range. It lives in tea-stained forest streams, and its timid, predominantly benthic nature means it does not always make an ideal community fish. Males guard eggs laid on the roof of a small cave, often formed from leaf litter.

Cynodon gibbus is a cynodontid from much of the Amazon basin, the middle and lower Orinoco, and the Rupununi River in Guyana. A pelagic fish of main river channels and larger tributaries, it grows to around 280 mm SL. It is rare in the trade but arguably more suitable for the home aquarium than some of its better-known relatives, given its size and relatively docile behaviour. Being easily dominated, it is best kept alone or with similarly sized, non-aggressive fishes.

The porthole catfish, Dianema longibarbis, is a peaceful callichthyid catfish from the Amazon basin in Peru and Brazil. It is named for the row of spots running along the lateral line. All specimens in the trade are wild-caught and new imports tend to be delicate and susceptible to disease, but once acclimatised it usually proves very hardy and can live for over 10 years.

The flagtail catfish, Dianema urostriatum, is a peaceful callichthyid catfish from parts of the Brazilian Amazon basin. It lives away from the main river channels in slower creeks, tributaries, floodplain lakes and ponds. All specimens in the trade are wild-caught and new imports can be delicate, but once acclimatised it usually proves very hardy and adaptable, and suits the larger community tank.

The spadetailed checkerboard cichlid, Dicrossus maculatus, is a cichlid from the Rio Tapajós, Rio Maués and nearby areas of the Brazilian Amazon. Not commonly available in the trade, it is sometimes mistaken for D. filamentosus. A challenge to breed, it needs extremely acidic, very soft water for the eggs to hatch, and a brooding female herds her fry around the tank with signals from her ventral fins.

The bucktooth tetra, Exodon paradoxus, is a scale-ripping characin widespread in the Brazilian Amazon. The only member of its genus, it has teeth that allow it to tear scales from other fishes. It will relentlessly attack silver-coloured or shiny tankmates, even larger predators, so it is best kept as a large shoal in a species setup. Scaleless and non-reflective fish are generally left alone.

The silver hatchetfish (Gasteropelecus levis) is a freshwater hatchetfish found only in the lower Amazon basin in the state of Pará, Brazil. It spends almost all of its time at or just below the surface, and can leap from the water and glide for several metres to catch flying insects or escape predators. It lives in open water of larger igarapés, streams and floodplain lakes.

The common hatchetfish (Gasteropelecus sternicla) is a freshwater hatchetfish from South America, described from Suriname. Its distribution is questionable, with records from the middle Amazon, Venezuela, Guyana, French Guiana and the Río Paraguay basin. It spends almost all of its time at or just below the surface. The most frequently seen of the silver hatchetfishes, it is peaceful but nervous and shy.

Gastrodermus gracilis, long known as Corydoras gracilis, is a small armoured catfish from the central Amazon basin in Brazil, known from the rio Juriti in Pará to the rio Juma in Amazonas. Sometimes called 'shy cory' in the hobby, it has a lightish body with a dark arched stripe along the upper flank, a pattern shared with Brochis arcuata, C. narcissus and Hoplisoma urucu. Only in G. gracilis does the stripe end at the base of the upper caudal-fin rays. It apparently favours minor tributaries with dense riparian vegetation and acidic, tannin-stained water.

The Guaporé cory, Gastrodermus guapore, long known as Corydoras guapore, is an armoured catfish endemic to the rio Guaporé (Río Iténez) in northeastern Bolivia and western Brazil. Unlike most congeners it forms aggregations in midwater and spends much of its time away from the substrate, with a large eye, a more terminal mouth and a strongly forked caudal fin to match. It partly feeds on pelagic zooplankton, so live Daphnia and Artemia belong in its diet. Similar species such as Hoplisoma simile lack these adaptations.

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.

Geophagus altifrons is a large cichlid from the middle-to-lower Amazon basin in Brazil, including the Xingu, Tapajós, Madeira, Negro and Purus. Despite being the type species it is among the most frequently-misidentified members of the genus, partly because populations from the Orinoco, the Guianas and the Tocantins are now species in their own right. In adults the dark midlateral marking is reduced to 1-2 scales or absent, a feature unique to the species, but juveniles are very difficult to identify.

Geophagus argyrostictus is a cichlid known only from the rio Xingu system in Brazil, including its major tributary the rio Iriri. It belongs to the five species outside the G. surinamensis group, all with a complete infraorbital stripe, and fish over 70 to 80 mm SL develop silvery reflective scales on the anterior flanks. Markedly more aggressive than most congeners, it is a substrate-spawner and does best in a group of 5-8.

Geophagus proximus is a large cichlid from the Amazon system in Peru and Brazil, from the río Ucayali along the Solimões-Amazon to the rio Trombetas. Rare in the hobby, its name is often attached to shipments of other Geophagus species. It has a dark preopercular marking, no bars on the flanks and a large, roughly oblong midlateral marking. It is found mostly in the lower reaches of rivers and in floodplain lakes, favouring clear and black water.

The January tetra, Hemigrammus hyanuary, is a small characin from the Amazon basin in Peru and Brazil. Also known as the costello or green neon tetra, it resembles an elongated head and tail light tetra, H. ocellifer, and is occasionally confused with it. The type specimen came from Lake Hyanuary near Manaus. It inhabits slow-moving rivers, tributaries and floodplain lakes and tends to lose colour in alkaline water.

Hemigrammus levis is a small characin native to the Brazilian Amazon, found in slow-moving rivers, tributaries and floodplain lakes. A rather rare fish in the UK hobby, it occasionally shows up as a contaminant among imports of more popular species. Like all Hemigrammus, its taxonomic status is Incertae Sedis, and most experts agree the genus needs a full revision.

The severum, Heros efasciatus, is a cichlid from the Amazon main channel and the Rio Solimoes, also recorded from the Rio Xingu. One of the most popular and readily available cichlids in the hobby, it is sold in the standard green form and in gold. Many buyers do not realise it grows fairly large, often 20 to 25 cm in aquaria, and it needs a tank of at least 120 cm. Outside spawning it is fairly mild-mannered for its size.

The pretty tetra, Holopristis pulchra, is a small characin endemic to the Upper Amazon in Peru, found in slow-moving tributaries under forest cover. Also known as the garnet or black wedge tetra, it is hardy, inexpensive and a good choice for the beginner. The vast majority on sale in the UK come from commercial farms in Eastern Europe, and it does well in most general community tanks.

Hoplisoma copei, long known as Corydoras copei, is an armoured catfish from Peru, apparently endemic to the Río Pastaza basin and possibly the lower Río Marañón. It is not well known and rarely traded. It looks very similar to several congeners, particularly H. acrense and H. cruziense, and little has been written about it since its description.

Sand's cory, Hoplisoma davidsandsi, long known as Corydoras davidsandsi, is an armoured catfish apparently endemic to the rio Unini system in the lower rio Negro basin, Brazil. One of a group of rio Negro species with an oblique dark bar along the back, it shares with H. melini a bar that splits in two above the caudal peduncle. It has a pale orange area between the facial stripe and dorsal bar and no further dark markings on the flanks.

The palespotted cory, Hoplisoma gossei, long known as Corydoras gossei, is an armoured catfish from the rio Mamoré watershed in Rondônia state, northwestern Brazil. It is also likely to occur in northern Bolivia, since the Mamoré forms the border between the two countries at the type locality. Also known as 'smokey cory' and 'Gosse's cory', it shares its colour pattern with Brochis seussi from the same river, which has a noticeably prolonged snout. A form referred to as 'CW069' appears intermediate between the two.

Hoplisoma kanei, long known as Corydoras kanei, is an armoured catfish that appears to be native to the rio Negro basin in Brazil, possibly only the rio Branco drainage. Before description it was assigned the 'C' numbers C026 and C046. It is most easily confused with H. atropersonatum and sometimes traded as that species, but has dark markings in the anal and caudal fins, more numerous and smaller dark spots on the body, and a darker base colouration.

Hoplisoma loretoense, long known as Corydoras loretoensis, is an armoured catfish from the upper Amazon in Peru, growing to around 50 mm SL. The profile singles out its very long dorsal spine. Nothing is recorded of its habitat.

The false bandit cory, Hoplisoma melini, long known as Corydoras melini, is an armoured catfish from tributaries of the rios Negro, Caquetá and Orinoco in Brazil and Colombia. Its oblique dark bar along the back splits into two above the caudal peduncle, a feature shared only with H. davidsandsi, from which the dark markings on its flanks separate it. The rio Tiquié population is known in the hobby as 'C084', and a similar, slightly larger form from Peru as 'C085'.

The panda cory, Hoplisoma panda, long known as Corydoras panda, is an armoured catfish from the upper Amazon in Peru, named for dark and light markings that recall the giant panda. Wildly expensive when first imported in the late 1970s, it is now mass-produced, and virtually all fish in the trade are farmed. Wild fish live in clear and blackwater streams that cool to around 19 °C when Andean meltwater arrives.

The three-lined cory, Hoplisoma trilineatum, long known as Corydoras trilineatus, is an armoured catfish from the Amazon basin in Colombia, Peru and Brazil and coastal rivers of Suriname. Most of the fish sold as C. julii are in fact this species, and the two are very hard to tell apart without knowing where the fish were collected. Peaceful and hardy, it ranks among the very best choices for the newcomer to catfish and is one of the easiest Corydoras to spawn.

The vampire tetra, Hydrolycus scomberoides, is a predatory dogtooth characin from the central and upper Amazon in Brazil, Bolivia, Peru and Ecuador. Also sold as 'scomb' and 'sabre tooth tetra', it is regularly confused with the much larger payara, H. armatus. At up to 300 mm it still needs a huge tank and specialist care, and newly-imported specimens often refuse anything but live food.

The snowball pleco (L102), Hypancistrus inspector, is a suckermouth catfish from the upper rio Negro in Brazil and the Casiquiare in Venezuela. Brown to black with large whitish to yellow spots, it is most similar to H. contradens. It is normally collected from rocky rapids, is a cave-spawner with male brood care, and should not be kept with other Hypancistrus in order to prevent hybridisation.

L136 is an undescribed Hypancistrus from the rio Negro basin in Amazonas state, Brazil, collected in particular from the rio Demini. Highly variable in colour pattern, it has been assigned a series of L-numbers as a result. A peaceful cave-spawner with male brood care, it has been bred regularly in aquaria, but should not be kept with other Hypancistrus in order to prevent hybridisation.

Hyphessobrycon agulha is a small tetra known with certainty only from the rio Madeira system in the Amazon basin of Brazil, Peru and Bolivia. Relatively rare in the hobby, it is occasionally traded as the 'red-tailed flag tetra'. It lends its name to a group of closely-related species with a dark lower half of the body, especially above the anal fin, and it is very peaceful.

The ember tetra, Hyphessobrycon amandae, is a tiny characid from the rio das Mortes, a tributary of the Araguaia in Mato Grosso, Brazil. Also traded as the 'Amanda's', 'dwarf red', 'red' and 'fire' tetra, it grows to around 20 mm SL. Very peaceful and gregarious, it makes a good dither fish for Apistogramma and other dwarf cichlids and spawns often in a mature aquarium.

The flag tetra, Hyphessobrycon heterorhabdus, is a characid from Pará and Maranhão states in eastern Brazil, also known as 'Belgian flag tetra'. Its name has been misapplied to similar fishes across much of the Amazon, the Orinoco and the Guianas, and the true species may reach no further upstream than the rio Tapajós. It lives almost exclusively in small, shaded forest streams called igarapés.

The Loreto tetra, Hyphessobrycon loretoensis, is a small characid from the upper Amazon basin in Colombia, Peru and Ecuador. It is relatively popular in the hobby, but most traded fish are wild-caught, so availability can be sporadic. Most records are from forest streams and minor tributaries with tea-coloured water, overhanging vegetation and leaf litter.

The Peruvian tetra, Hyphessobrycon peruvianus, is a characid known only from the upper Amazon basin in Peru. Popular in the trade, it is sometimes confused with H. loretoensis and H. metae and has repeatedly appeared under the latter name in aquarium literature. A more elongate body, a dark band reaching the tips of the median caudal-fin rays and red markings at the base of both caudal lobes set it apart.

The lemon tetra, Hyphessobrycon pulchripinnis, is a characid from central Brazil, mostly recorded from the rio Tapajós basin. It is bred commercially in several countries, but the origin of the aquarium strain is questionable. Fish identical to it have been photographed in the lower Xingu, while a related 'orange red' form from the Tapajós may not be the same species.

The flame-back bleeding heart tetra, Hyphessobrycon pyrrhonotus, is a characid endemic to the rio Negro system in Amazonas state, Brazil. The smallest of the three 'bleeding heart' species, it alone has a red, wedge-shaped patch along the upper body from below the dorsal fin to the base of the caudal. It lives in shallow blackwater tributaries near Barcelos, among roots, branches and leaf litter.

Hyphessobrycon vilmae is a small characid that appears to be endemic to the upper rio Tapajós basin in Amazonas and Mato Grosso states, Brazil. It is occasionally traded as 'chocolate neon tetra', and has a continuous, solid dark lateral stripe with no obvious humeral blotch. Generally peaceful, it is best kept in a mixed-sex group of at least 8-10.

L231 is an unidentified Hypostomus, a large suckermouth catfish said to be exported from the upper Amazon region of Peru. Precise details of its origin are lacking. It grows to 250 to 300 mm SL and needs an aquarium of at least 180 by 60 cm, and it is unclear whether it is the same species as the similarly nameless L266.

The Rio Negro chocolate cichlid, Hypselecara coryphaenoides, comes from rivers in Brazil and Venezuela including the Negro, Trombetas and Tapajós. It is much rarer in the trade than H. temporalis, from which it differs in a more elongate body, darker colour and a flank blotch on and above the lateral line. It lives in sluggish forest tributaries with dark, acidic water.

The chocolate cichlid, Hypselecara temporalis, is a large cichlid from Peru, Colombia, Venezuela and Brazil. It most often inhabits silt-laden, slow-flowing rivers, and has been collected in the Ucayali, Amazonas, Solimões, Amapá and Oyapock. Although it reaches 30 cm, it is quite a placid species and can be kept in a community of large fish in a suitably-sized tank.

Traded as the 'red line lizard tetra', Iguanodectes adujai is a characin from the rio Negro in Brazil and the upper Río Orinoco in Venezuela. It is exported alongside the similar-looking I. geisleri, and differs in lacking the black lateral stripe beneath the red stripe and in having 28 to 34 anal-fin rays (20 to 25 in I. geisleri). It is assumed to live in smaller tributaries containing pristine blackwater.

Iguanodectes geisleri is a characin from the rios Madeira and Negro in Brazil and the upper Río Orinoco in Venezuela. Traded with the similar-looking I. adujai as the 'red line lizard tetra', it differs in having a black lateral stripe beneath the red stripe and 20 to 25 anal-fin rays (28 to 34 in I. adujai). Adult males carry red markings in the pectoral, pelvic, anal and caudal fins.

The green line lizard tetra, Iguanodectes spilurus, is a characin found throughout the Amazon, Orinoco, Essequibo and Tocantins river systems. The most widespread Iguanodectes species, it has also been called the 'slender', 'spindle' or 'iguana' tetra, and differs from its congeners in its translucent dorsal and anal fins, lack of a red lateral stripe and prominent dark caudal-fin marking. It is sensitive to poor water conditions.

The striped headstander, Laemolyta taeniata, is an anostomid from the central Amazon basin, also recorded from the Orinoco system in Venezuela. The largest-growing member of the genus, to 288 mm SL, it is rarely seen in the aquarium trade. Something of a habitat generalist, it migrates into flooded forest in the wet season and has been seen in large migratory shoals with Leporinus fasciatus and L. agassizii. Water quality is of the utmost importance, and anostomids are prodigious jumpers.

The sturgeon catfish, Lamontichthys filamentosus, is a loricariid from the central and western Amazon in Brazil, Peru, Ecuador and Bolivia. Above 60 mm SL the pectoral-fin spine extends into a filament that can be over four times the length of the first branched ray, and the dorsal-fin spine carries a similar extension. Relatively common in the hobby but not easy to maintain, it needs clean, well-oxygenated water and a mature aquarium with plenty of algae-covered surfaces.

The marbled pim, Leiarius longibarbis, is a large pimelodid catfish from the Rio Orinoco, Rio Essequibo and Amazon basins. It grows to around 80 cm and can live for well over 20 years, and whether it should be considered an aquarium subject at all is debatable. Much of the literature still lists it as L. marmoratus, a name treated as a junior synonym since a reclassification in 2003.

The South American lungfish, Lepidosiren paradoxa, is found across the Amazon, Rio Paraguay and lower Paraná basins. The only lungfish known from South America, it is an obligatory air breather and survives the dry season by aestivating in a mucous cocoon inside a burrow in the mud. It can reach 125 cm and live for well over 20 years, so whether it should be considered an aquarium subject at all is debatable.

The galaxy plec, Leporacanthicus galaxias (L029), is a suckermouth catfish from the Amazon, Tocantins and other river basins in Brazil. Also sold as the vampire or tusken plec, it lives in rapids and other fast-flowing waters. Four similar undescribed variants, L007, L240, L241 and L294, are known as L. cf. galaxias and are best referred to by their L numbers.

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.

Leporinus brunneus is an anostomid from the rios Madeira and Negro in Brazil, the Orinoco in Venezuela and Colombia, and the Casiquiare canal. The largest officially recorded specimen measured 256 mm, and an aquarium with base dimensions of at least 210 by 60 cm is needed.

The banded leporinus, Leporinus fasciatus, is an anostomid from the Amazon and Orinoco systems and coastal Guyana, Suriname and French Guiana. Young fish are often sold without warning of their size and requirements, and it is fairly ubiquitous in public aquarium displays. It is frequently confused with L. affinis, and its dark body bars multiply with age, from five in young fish to around ten in adults.

The threespot leporinus, Leporinus friderici, is an anostomid from much of the Amazon system, with further records from the Guianas and Trinidad. It grows to 350 to 400 mm and needs an aquarium with base dimensions of at least 240 by 90 cm. Across this enormous range the fish differ in morphology and, especially, colour pattern.

The striped pike cichlid, Lugubria strigata, is a large pike cichlid from the lower Amazon basin in Brazil, away from the main river itself. One of the more commonly available pike cichlids in the UK, it is often bought by fishkeepers unaware that it grows to around 40 cm. It can be aggressive, especially towards conspecifics, and is reported to be susceptible to hole in the head disease.

The tiger pike cichlid, Lugubria tigrina, is a pike cichlid known only from the Rio Trombetas in the Brazilian Amazon. It is rarely seen in the UK hobby, and males carry the prominent black spots and stripes behind the common name. Growing to around 30 cm, it can be aggressive towards conspecifics and will eat any fish small enough to be considered food.

The ornate tetra, Megalamphodus bentosi, is a small characid whose type locality lies on the main channel of the lower Amazon at Óbidos, Brazil. It is very similar to a number of congeners, some of them undescribed, and the rosy tetra is the one most often seen in the trade. It may also be sold as 'Bentos' tetra' or 'white-tipped tetra'. It mostly inhabits sluggish tributaries, side arms and forest lakes, often around submerged roots, branches or plants.

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 bleeding heart tetra, Megalamphodus erythrostigma, is a characid from the upper Amazon basin where the borders of Brazil, Peru and Colombia meet. The best-known of three similar species in the 'bleeding heart' subgroup, it has the reddish humeral spot found in no other characid. Generally peaceful, although adult males are territorial to an extent, it mostly inhabits sluggish tributaries, side arms and forest lakes.

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 lesser bleeding heart tetra, Megalamphodus socolofi, is a characid known only from the rio Negro basin and the rio Nhamundá in Brazil. One of three similar species in the 'bleeding heart' subgroup, it shares their reddish humeral spot, found in no other characid. Generally peaceful, although adult males are territorial to an extent, it mostly inhabits sluggish tributaries, side arms and forest lakes.

The bar-tailed hoplo, Megalechis picta, is a callichthyid catfish widely distributed east of the Andes in Brazil, Venezuela and Guyana. It is recorded from the Amazon, Orinoco and upper Essequibo systems. Previously referred to as M. thoracata, it can be told from that species by a dark vertical bar in the caudal-fin and a longer dorsal-fin spine. Peaceful and hardy, it can even tolerate hypoxic conditions, and the male builds a nest.

The silver dollar, Metynnis hypsauchen, is a relative of the piranhas with a patchy distribution in Guyana, Brazil, Peru and Bolivia. Sometimes called the plain metynnis, it is sold under the same name as the very similar M. argenteus and differs in the black blotch above and behind each eye. A striped form is not a distinct species. An avid plant-eater, it is best kept in a group of at least five.

Metynnis lippincottianus is a spotted silver dollar from Brazil and French Guiana, found in the lower and middle Amazon and the Oyapock system. It is occasionally seen for sale, sometimes as 'silver dollar', and its spotted pattern tells it apart from M. argenteus and M. hypsauchen. The spots are less pronounced than in M. maculatus, with which it shares a common name. The precise extent of its range is unclear.

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 ceros tetra, Moenkhausia ceros, is a small characid from the Amazon basin in Peru and Brazil. Rare in the UK hobby, it occasionally shows up as a contaminant among imports of more popular species. It inhabits slow-moving rivers, tributaries and floodplain lakes. Moenkhausia is used as a catch-all for many small characins, and most experts agree the genus needs a full revision.

The redhook, Myloplus rubripinnis, is a relative of the silver dollars from much of northern South America, including the Amazon and Orinoco. Commonly sold as a silver dollar, it can be told apart by its black-trimmed, red anal fin and grows much larger, to around 25 cm. Given a large enough aquarium, correct feeding and good water quality it should not pose many problems. It is still widely referred to as Myleus rubripinnis.