Napo

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 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 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.

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 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 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 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 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.

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 Pastaza cory, Corydoras pastazensis, is an armoured catfish from the upper Río Pastaza basin in Ecuador and the ríos Ucayali and Puinahua in Peru. The Río Tigre form was raised to species status as C. orcesi, a decision not followed by all authorities. The two are relatively easy to tell apart: in C. pastazensis the dark vertical bar breaks up or tapers off low on the body, and the body is peppered with numerous small dark spots.

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 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 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 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 dwarf pencilfish, Nannostomus marginatus, is a lebiasinid of Guyana, Suriname and the middle-to-lower Amazon in Peru, Colombia and Brazil. Enduringly popular, it lacks the red body colour of males of the related N. mortenthaleri and N. rubrocaudatus, showing three dark lateral stripes with no red or purple between them. Colour varies between populations, and its small size and timid nature make it a poor community fish.

The three-lined pencilfish, Nannostomus trifasciatus, is a lebiasinid widespread in the western Amazon basin in Brazil, Peru, Colombia and Bolivia. Fairly ubiquitous in the trade, it is less demanding than many congeners and a good choice for a newcomer to pencilfishes. Many fish on sale are farmed, and wild populations vary in colour pattern, one being marketed as 'super red' for its unusually long red stripe.

The bola pleco, Peckoltichthys bachi, is a loricariid catfish from the upper Amazon region in Brazil, Colombia, Ecuador and Peru. It has been assigned several L-numbers, including L146 from Colombia and L232 from the Río Putumayo/Içá, and has been exported under other generic names including Hemiancistrus and Sophiancistrus. Its mottled colour pattern separates it from most Peckoltia species, and it lives among submerged grasses and branches in flowing water along the margins of medium to large rivers.

The demon eartheater, Satanoperca jurupari, is a cichlid recorded throughout much of the Amazon basin in Brazil, Bolivia, Peru, Ecuador and Colombia. In aquarium literature it is frequently confused with S. leucosticta, which has prominent white spots or vermiform markings on the sides of the head. Its precise identity is a confusing issue, and populations from the Tapajós, Xingu, Araguaia and Paraná are genetically distinct and may represent separate species.

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.

The saddle cichlid, Aequidens tetramerus, is a cichlid found across much of northern South America, from the Amazon and Orinoco basins to the Guianas. The type species of its genus, it occurs in several colour forms, and fish from Ecuador and Peru are sought after for the red or orange colouration on the lower head and belly. As currently recognised it is likely to represent a group of related fishes, some of which may be described as distinct species.

Boulengerella cuvieri is a pelagic ctenoluciid characin from much of the Amazon basin, the Río Orinoco and coastal drainages of the Guianas. The largest officially recorded specimen measured 675 mm, but it appears to grow larger, possibly beyond 800 mm. Given that size and its natural behaviour it is largely unsuitable for the home aquarium. Its entire dorsal-fin base lies ahead of the anal-fin origin, a character shared only with B. lucius and B. xyrekes among ctenoluciids.

The piraíba, Brachyplatystoma filamentosum, is the largest catfish of the Amazon basin, also found in the Orinoco and river systems of the Guianas. Adults typically measure 2 to 2.5 m and weigh over 150 kg. In the Amazon only fish over around 160 cm are called 'Piraíba', and smaller ones 'filhote'. It is suitable only for public aquaria and a very small minority of private aquarists.

The slobbering catfish, Brachyplatystoma platynemum, is a large migratory pimelodid catfish from the Amazon and Orinoco basins. The name refers to its relatively thick barbels, which give the impression that the fish is drooling. It travels considerable distances along deeper, flowing channels, and sexually mature adults have been observed in the upper rio Madeira basin, some 3000 km from the estuary. It grows to 1000 mm SL.

The dourada, Brachyplatystoma rousseauxii, is a large migratory pimelodid catfish from the Amazon and Orinoco drainages and rivers of the Guianas. Juveniles feed in the Amazon delta, while sexually mature adults are found only in the western Amazon. Some populations cover as much as 5500 km during migration from the delta, the longest known in any freshwater fish, and it is heavily fished during its upstream movement. It grows to 1900 mm SL.

The piramutaba, Brachyplatystoma vaillantii, is a large migratory pimelodid catfish from the Amazon and Orinoco watersheds and rivers of the Guianas. Juveniles feed in the Amazon delta before migrating upstream in massive numbers, when they are subject to intensive capture by commercial and artisanal fisheries. Sexually mature adults have been observed in the rio Caquetá basin, some 3500 km from the estuary. It grows to 1050 mm SL.

Brochis ambiacus, long known as Corydoras ambiacus, is an armoured catfish from the upper Amazon tributaries of Peru, Brazil, Colombia and Ecuador, described from the Río Ampiyacu. Its name is commonly misapplied to similar-looking fishes, particularly B. agassizii, and the colour pattern is variable. Cope described a large black spot covering the front half of the dorsal fin, and fish matching this are far more common in the trade than those matching B. agassizii.

The skunk cory, Brochis arcuata, long known as Corydoras arcuatus, is an armoured catfish from the upper Amazon region in Brazil, Peru, Ecuador and Colombia. It is among the more popular Corydoras in the hobby and is also known as the 'arched cory' or C020. Several similar-looking congeners exist, particularly Hoplisoma urucu, in which the black body stripe ends behind the eye, and the larger C. narcissus from the rio Purus.

The blacktop cory, Corydoras acutus, is an armoured catfish from the upper Amazon basin in Brazil, Peru, Ecuador and possibly Bolivia. It can be confused with three similar fishes known as C024, C077 and C109. C024 and C109 occur thousands of kilometres outside its range, but C077 lives alongside it in the rio Abunã and is only known to differ in growing smaller. Some specimens lack the dark marking in the dorsal fin.

The elegant cory, Gastrodermus elegans, long known as Corydoras elegans, is an armoured catfish from the western Amazon basin in Peru, Ecuador and Brazil. Unlike most congeners it spends a fair amount of time away from the substrate, often forming groups in midwater. It gives its name to the unofficial 'C. elegans group' of similar species, which includes G. nanus and G. undulatus plus many C- and CW-numbered fishes of uncertain status.

The silver arowana, Osteoglossum bicirrhosum, is a large predator from the Amazon basin, plus river systems in Guyana and French Guiana. Reaching 80 cm, it is largely unsuitable for the home aquarium, and although juveniles are readily available, few private aquarists can house an adult long-term. Juveniles have a single dark lateral stripe, while in those of its only congener, O. ferreirai, most of the body and fins are dark.