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This species, which may also be referred to by the alternative vernacular names 'spiny catfish', 'painted talking catfish' or 'chocolate raphael', isn't particularly common in the trade and most often exported only as bycatch among shipments of Platydoras armatulus. It appears very similar to A. cataphractus with the most useful external distinguishing character being the presence of pale blotches on the dorsal surface, between the dorsal and caudal fins, in....

This species is not normally aggressive towards conspecifics with juveniles in particular exhibiting a marked schooling instinct. Older individuals tend to be more solitary but still group together from time-to-time, and it's best maintained in numbers of four or more. One important point to note is that acestrorhynchids are can...

The vernacular name of this fish is derived from its appearance and behaviour, rather than a genetic association with the marine barracuda, and it's also sometimes referred to as 'pike characin' or 'spotted cachorro' with local vernacular names including 'Grand dent-chien' (French Guiana), ' Cachorrinho' or 'Ueua' (Brazil). Although most species of Acestrorhynchus appear superficially similar to one another most exhibit distinguishable external chara...

This species is a member of the putative A. nasutus group of closely-related species within the genus alongside A. nasutus, A. maculipinna and A. isalineae. These are characterised by possession of two dark, longitudinal stripes, one running from the tip of the snout to the base and the other from the posterior edge of the lower maxilla to the underside of the caudal peduncle.

An obligate piscivore capable of consuming quite large prey in relation to its body size although it tends to focus on smaller prey such as tetras and related species. Newly-imported specimens may refuse to accept anything but live fishes although most can be weaned onto dead alternatives once they recognise them as edible, and some even learn to accept dried foods.

The genus Ageneiosus was at one point classified in the family Ageneiosidae alongside the genus Tetranematichthys, but this was not accepted by all authors. The grouping remains poorly-studied with the last major revision having been conducted by Watson (1990) in his unpublished dissertation, in which A. inermis was included under the currently synonymous name A. brevifilis. It can be separated from the majority of the genus (except A. marmoratus) by possession of a truncate caudal fin, and from...

Apparently this species is polymorphic with body patterning varying significantly depending on locality. Individuals collected from black water habitats tend to be noticeably darker in overall colouration, for example, with this being particularly evident among populations from the Guiana Shield. The genus Ageneiosus was at one point classified in...

This species is not always identified correctly with its name used for the unidentified common bristlenose and other similar species, while the fish itself has been referred to as A. hoplogenys and assigned the L-number L183. Images and information describing it it in much of the available literature confirm this confusion.

A biotope-style set-up could consist of a sandy substrate, piles of smooth rocks and driftwood roots and branches, some of which should penetrate the water surface. Aquatic vegetation can be included if you wish but is likely to be eaten.

Apistogrammas are identified by the use of "A numbers"in a similar fashion to the "L number" system used to identify loricariids. Apistogramma brevis is identified as A168. Additionally, apistos are also grouped into type families and this species is the species type of the brevis group. Unlike some apistogramma species, a. brevis occurs only in a relatively small range and has not been found outside this. personata complex gibbiceps group...

The German term 'breitbinden' translates literally as "broad-banded" and refers to the uniformly broad suborbital stripe seen in males of this 'species' which remains undescribed despite being known in the aquarium hobby for several decades. It's often imported as bycatch among shipments of wild-collected A. iniridae. Some of the populations have also been assigned th...

An obligate predator by nature, but captive specimens readily accept strips of white fish, whole shrimp, earthworms, and similar once they are recognised as food. Adult individuals are unlikely to require feeding on a daily basis with 1-2 meals per week sufficient.

This species is also referred to as 'velvet cichlid', 'red oscar', 'tiger oscar', or 'marble cichlid'. It is a popular aquarium fish although its adult size and typical life-span of 10-20 years must be taken into account before purchase. Numerous ornamental strains are now available, and while care is more-or-less identical for all of them a degree of additional care must be taken with the 'long-finned' variety which is a little less competitive than other forms.

A. bimaculatus is not a popular aquarium fish but is available on occasion exception, most often as a contaminant among shipments of other species. It's identity is also in question to an extent with the name currently applied to what is considered to represent a species complex comprising at least four taxa.

Recorded throughout much of the Amazon basin, with its range extending eastwards from the Ucayali system in Peru as far as the Tocantins drainage which flows into the Atlantic alongside the Amazon at its delta. The southern extremity of its range appears to be the Río Mamoré in Bolivia, a tributary of the rio Guaporé, and the northern limit the Essequibo basin, Guyana.

Populations known in the aquarium trade include 'Cuao', 'Orinoco', 'San Antonio', and 'Sipapo Ventuari'. B. wavrini and its congener B. cupido can be separated by body shape and position of the dark blotch on the posterior portion of the flank. In B. cupido the body is relatively compact and the blotch located above the upper lateral line, whereas in B. wavrini the body is noticeably elongate and the blotch on or below the upper lateral line.

At time of writing there exists no scientific evidence that the different populations of this species seen in the aquarium trade (see 'Distribution') represent anything other than a single, widely-distributed species although some exibit minor morphological differences including relative body depth, longer fin rays in the unpaired fins and yellow or orange colouration in the paired fins. There is apparently a form from the upper rio Negro which may turn out to be distinct but it's...

Boulengerella differs from Ctenolucia, the only other genus currently contained in the family Ctenolucidae, by a series of derived features including possession of 87-124 (vs. 45-50) lateral line scales, presence of a strongly (vs. weakly) developed fleshy appendage at the tip of the snout and absence (vs. presence) of fleshy flaps on the lower jaw. Within the order Characiformes the family Ctenoluciidae is also distinguished by a set o...

Both species also possesses a broader dark midlateral stripe on the body which tends to be more well-defined in B. lateristriga than in B. maculata. Colour pattern in B. maculata varies considerably with some specimens noticeably paler than others, for example, and the the broad midlateral stripe usually less intense in such individuals. This does not app...

Several Brachyrhamdia species have developed colour patterns that mimic syntopically-occurring Corydoras spp. throughout the life-cycle, and the remainder may mimic Otocinclus or smaller Corydoras spp. when juvenile. Among other catfishes they're closely-related to members of the genus Pimelodella, but differ in...

Gasteropelecids are commonly-referred to as 'freshwater hatchetfishes' due to their heavily-keeled body shape which has evolved in such a way due to possessing an enlarged, heavily-muscled pectoral girdle, and which resembles the shape of a hatchet head. They are sometimes said to be capable of propelled flight above the water surface by beating their pectoral fins but in fact this is not the case and was disproven by Wiest (1995) who used...

C. strigata is an enduringly popular species in the aquarium hobby but is not bred on a commercial basis with all fish offered for sale collected in the wild. It can be told apart from other members of the genus by its larger adult size and dark, marbled colour pattern appearing as a series of dark and light stripes running diagonally across the body below the lateral line. This colour pattern is variable and popul...

All members of the family Auchenipteridae are thought to practise internal insemination and females can carry mature, unfertilised eggs and sperm packets inside the body for unspecified periods of time. When conditions are satisfactory fertilisation is triggered and the eggs deposited, and there is n...

Omnivorous and will accept most foods offered, with the stomach contents of wild specimens varying on a seasonal basis but mostly comprising insects and insect larvae (orders Trichoptera, Hemiptera, Homoptera) plus some terrestrial fruits and even scales of other fishes (Sánchez et al., 2003). In the aquarium offer live Daphnia, Artemia, Moina, bloodowrm, etc., vegetable matter in the form of blanched spinach, lettuce, cucumber, fruit, algae wafers, etc., and good quality, sinking dried foods.

This species is also referred to as 'South American puffer', 'SAP', 'Amazonian puffer', 'Peruvian puffer', or 'Brazilian puffer' in the ornamental trade. Within the genus Colomesus, C. asellus can be immediately identified by possessing a unique transverse row of dermal flaps across the chin which is absent in its congeners C. psittacus and C. tocantinensis.

Known from the middle and upper Amazon river basins in Brazil, Peru, Ecuador and Colombia. Type locality is 'Amazon River at Obidos, Cudajas, and Tabatinga; Rio Negro, Brazil.' It apparently practises an interesting reproductive strategy in which the eggs are deposited in a shallow depression excavated from the substrate and guarded by the male.

This species is quite common in the aquarium trade although normally misidentified as the congeners C. nattereri or the very similar C. meinkeni. It was considered synonymous with C. nattereri for a number of years and was also referred to as C. cf. meinkeni by Zarske and Géry (2006) befo...

This species has been widely referred to as the congener C. nattereri in aquarium literature both prior to and post-publication of its official description in 2006. The two can be told apart quite easily by the fact that C. nattereri possesses a dark lateral stripe while C. meinkeni does not. C. meinkeni can be distinguished from all congeners by the followi...

This species is sometimes traded as C. sp. 'red line', 'spotted tetra' or as its congener C. nigrofasciata. In the past it's name was also widely applied to the fish now identified as C. callolepis and C. meinkeni, and this misidentification continues to an extent although the two are easily-distinguished by the fact that C. nattereri is the only one of the three possessing a dark lateral stripe on each side of the body.

The most obvious distinguishing characters are that the black marking in the upper part of the body is restricted to the area beneath the dorsal-fin and extends into the majority of the fin , while the paler patch anterior to it, on top of the head, is yellowish rather than orangish. Additional diagnostic characters have proven unavailable thus far since it was described in a hobbyist magazi...

The type series was said to have been collected from a "whitewater area", but images of the rio Unini depict a blackwater system typical of the rio Negro basin, and this is supported by empirical evidence. There are sections of rapidly-flowing water so perhaps this is what the author was referring to. Habitats should therefore comprise tributaries and areas of flooded forest where the water is...

Endemic to the upper rio Negro basin in Amazonas state, northern Brazil, and Amazonas state, southern Venezuela. One specific locality is Igarapé Muiá (00°09'03"N 66°48'10"W). Type locality is 'Upper Rio Negro, eastern Amazonas, Brazil', which is thought to refer to forest brooks crossing the "new army road", north of São Gabriel da Cachoeira municipality.

C. incolicana was the first recipient of a 'C' number (see below) in 1993 and was described the same year. Unfortunately its description was published in an aquarium hobbyist magazine, and we have been unable to obtain a copy to date meaning its diagnosis is unavailable. It is therefore difficult to identify accurately, not least because its type locality is in a relatively remote area, and there exist a number of superficially similar Corydoras species or populations in the aquarium trade.

Prior to description C. kanei was assigned the 'C' numbers C026 and C046. Among congeners it is most easily-confused with, and sometimes traded as, C. atropersonatus, but can be identified by presence (vs. absence in C. atropersonatus) of dark markings in the anal and caudal fins, presence of numerous, smaller (vs. fewer, larger) dark spots on the body, and an overall darker (vs. paler) base colouration.

In the aquarium hobby, the population from the rio Tiquié has been referred to as 'C084', while a similar, but larger, form from the Río Huallaga in Peru is known as 'C085'. Both forms have been marketed as C. sp. 'mega metae'. The existence of multiple, similarly-coloured species which coexist and sometimes form mixed schools is relatively common in the genus.

This species is currently the only described member of its genus although colour pattern and morphology vary considerably across its range. You may see reference to this species being the only fish species to possess infra-red vision, but other species also possess this ability and we suspect that infra-red plays an important role in the reproductive cycle of many fishes.

This species is rare in the aquarium trade but is arguably more suitable for the home aquarium than some of its better-known relatives given its adult size and relatively docile behaviour. Other vernacular names include 'Dientón' (Peru), 'Perrito' (Ecuador), 'Payara-chata' or 'Payarin' (Venezuela) and 'Icanga', 'Minguilista' or 'Peice-cachorro' (Brazil), some of which are also applied to related species.

Despite its designation as type species this is among the most frequently-misidentified members of the genus. This is in part because its natural distribution was earlier considered even more extensive than the still-substantial range recognised today, with populations from the Río Orinoco, Guianas and rio Tocantins now recognised as species in their own right.

This species is rare in the hobby although other species are sometimes sold under the name. It's a member of the nominal G. surinamensis 'group' of closely-related species within the genus and can be identified by a combination of characters including: possession of dark preopercular marking; four parallel, ventrally-inclined bars on each flank (normally visible only when the fish are stressed, spawning or preserved); dark lateral spot positioned within the second vertical bar; caudal fin red with variable pattern of large, iridescent blue to white spo...

This species may be referred to using a variety of names including 'scomb', 'sabre tooth tetra', 'sabre tusk barracuda', 'dog tooth characin, 'vampire fish', 'Cachorra' or Pirandirá (the latter two names being used in Brazil where they're also applied to congeners). It's regularly confused with the payara, H. armatus, though that species grows considerably larger, is pop...

H. inspector can be told apart from other described species in the genus by the following combination of characters: colour pattern comprising brown to black base with large whitish to yellow spots; adpressed dorsal-fin not reaching the adipose-fin spine; spots on head much smaller than on rest of body; spots in the upper caudal-fin lobe combining to form bands in adults; 24 plates in the mid-ventral series.

L136 and its variants are collected in the rio Negro basin, Amazonas state, Brazil, and in particular the rio Demini, a northern tributary flowing into the central Negro in the municipality of Barcelos. Collection details for LDA05 and LDA06 are currently unclear but presumably in the vicinity. This unidentified 'species' is highly variable in terms of colour pattern, and it has been assigned a ser...

This is the smallest of three similar-looking species most commonly-referred to as the 'bleeding heart' subgroup, the other two being H. erythrostigma and H. socolofi. All possess a reddish humeral spot which is not present in any other characid with other shared characters including possession of 6 -14 maxillary teeth, 7-9 scales above the lateral line, 5-7 scales below the lateral line and 26-33 anal fin rays.

This species is an opportunistic omnivore by nature. The stomach contents of wild specimens from the rio Padauari were composed of fruit remains and aquatic insects with the former constituting 99% and latter 1% of all items consumed. Stomachs of individuals from igarapé Água Boa cont...

This species is known from the rio Negro within the Brazilan Amazon basin and upper Río Orinoco system in Venezuela. Type locality is 'Rio Adujá, Rio Itú, tributary of middle Rio Negro, Amazonia, Brazil'.

I. geisleri is typically exported for the aquarium trade alongside the similar-looking congener I. adujai (Géry, 1970) but can be identified by presence (vs. absence in I. adujai) of a black lateral stripe on the body beneath the red stripe, and possession of 20-25 (vs. 28-34) anal-fin rays.

L. taeniata is the largest-growing and second most widely-distributed member of the genus although it's a rarely-seen in the aquarium trade. It can be distinguished from all congeners since it uniquely possesses 5 lateral scale rows between the lateral line and dorsal-fin origin (vs. 4 or 6–8 in the remaining species).

Décor is relatively unimportant and maintenance simple provided sufficient space is available. A natural-style arr...

This species is also referred to as 'black-anded leporinus', 'striped leporinus' and 'eight-banded leporinus'. Young specimens are often traded for aquaria without warning as to their potential size and requirements, and as a result it's fairly ubiquitous in public aquarium displays.

This is the smallest member of the genus and rarely traded in numbers, though it's a relatively common contaminant among shipments of wild fishes from Manaus. Unlike other Nannostomus spp. it does not exhibit a specific colour pattern of spots or bars at night-time, rather displaying an overall paleness. The family Lebiasinidae is included in the order Characiformes and sometimes split into the nominal subfamilies Lebiasininae a...

This is the type species of the genus, fairly ubiquitous in the aquarium trade, and represents an excellent choice for the newcomer to fishkeeping since it's less demanding than most congeners. It's sometimes referred to as 'Beckford's pencil fish' or 'brown pencilfish'. Don't worry if your fish look different when you switch on the aquarium lights after dark or in the morning as like most Nannostomus species it assumes a cryptic, vertically-barred colour pattern at ni...

This species has been referred to the genera Poecilobrycon and Nannobrycon in the past and in the aquarium hobby is also known as 'rocket', 'brown', 'brown-tailed', 'diptail', or 'tubemouth' pencilfish.It's a popular aquarium fish and has an interesting oblique swimming-style, a behavioural trait shared only with N. unifasciatus among congeners. In the original description the colour pattern is given by Steindachner as a brown lateral stripe exte...

There also exist a number of minor differences in colour pattern between populations. For example some Peruvian forms have yellow pigmentation on the body and fins, and those from Guyana and Suriname possess a short red stripe on vertical scale rows 6-9, above the central dark stripe on the body. Rio Negro forms have a similar red stripe but overlapping the central dark stripe and extending along most of the flank, while a form from Colombia has an elongate red stripe which is broken in two beneath the dorsal-fi...

This species is also known as 'Marilyn's pencilfish'. It's rarely traded in numbers and more often seen as bycatch among shipments of other species, particularly Paracheirodon axelrodi. It can be identified by the following combination of characters: three dark lateral stripes (sometimes referred to as primary, secondary, and tertiary); nocturnal oblique bars relatively narrow, with the anterior bar reaching, but not extending past, the anterior base of the dorsal-fi...

Wild populations vary in colour pattern depending on origin, and some populations have previously been described as distinct species. A form from Peru has a particularly silvery body colour, for example, while another, marketed as 'super red' possesses an unusually long red stripe on the body, extending much of the length of the dark central stripe. A population from around Boa Vista in the rio Branco system, Pará state, Brazil has an ocellus o...

It was initially going to be described as Hyphessobrycon cardinalis by Myers and Weitzman (1956) but just before this was due to be published Schultz presented an alternative description in the hobbyist magazine 'Tropical Fish Hobbyist' and named the fish after the publication's founder, Dr. Herbert R. Axelrod. A significant proportion of the fish available in the aquarium trade are still wild caught or derive from community-led breeding projects such as Project Piaba in the middle Negro region, where this sp...

For aquarists perhaps more useful are the subtle differences in colour pattern with P. simulans differing from both P. innesi and P. axelrodi in possessing a greener (vs. bluer) lateral stripe which covers more (vs. less) of the eye/head and extends to the caudal-fin base (vs. terminating anterior to caudal-fin base), a lesser (vs. greater) amount of relatively duller (vs. brighter) red pigmentation on the flanks. The taxonomic history of all three species is complicated with earlier authors such as Géry (1960, 1977) ten...

Quite widely distributed having been recorded from Brazil, Colombia, Peru and Venezuela. It's been collected from the upper parts of several major river drainages including the Río Negro, Río Orinoco (including the Río Inírida and Casiquiare canal) and Río Solimões. The type series was collected from 'Igarapé Préto', Brazil, said to be 60 kilometres to the south of the Colombian border city Leticia. Populations from Colombia and Brazil tend to be more intensely-coloured, and the Peruvian populations may apparently represent an undescribed species.

Mostly collected in the in the rio Negro basin, Amazonas state, Brazil, and in particular the rio Demini, a northern tributary flowing into the central Negro in the municipality of Barcelos. P. leopardus was described from the Rupununi River in Guyana and the identity of this fish thus remains unconfirmed. This 'species' is also traded simply as 'leo...

Pterophyllum leopoldi can be differentiated from other members of the genus by the presence of up to 11 vertical stripes on the body, though often only the 3 largest, boldest stripes can be seen. This species also shows a dark patch over the operculum. In adult specimens, a red/maroon hue over the back and fins is characteristic of the species, leading some to believe the most colourful natural form Angelfish. The name-sake roman nose possessed by the fish is also very distinctive and used as a meristic feature.

This species is relatively rare in the ornamental trade, where it is sometimes confused with its similarly-patterned congeners S. daemon and S. lilith. These three species all possess 1-3 dark blotches on the side of the body and a relatively large ocellus on the upper caudal-fin base, characters that immediately separate them from the remainder of the genus which lack blotches on the body and have a relatively small ocellus on the upper caudal-fin base.

S. daemon is relatively common in the aquarium trade but is by no means easy to maintain, with particular attention to space, diet, water quality, and chemistry required in order for it to thrive. It can be distinguished from other members of the genus by possessing two dark blotches on the flank and a prominent ocellus at the caudal-fin base. Among the named species it is most similar to...

S. jurupari is also known as 'demon fish', 'jurupari earth eater', 'green horse face', or simply 'jurupari' in the aquarium hobby. It can be distinguished from other members of the genus by the following combination of characters: presence of a relatively small dark ocellus on the upper caudal-fin base; absence of well-defined dark blot...

Despite its extensive natural distribution S. lilith is uncommon in the ornamental trade, where it is sometimes referred to as 'one-spotted demon fish' or 'one spot eartheater'. It can be distinguished from other members of the genus by possessing a single dark blotch on the flank and a prominent ocellus at the caudal-fin base. Among the named species it is most similar to S. daemon, but that species possesses two blotches on the flank.

This species occasionally appears in the ornamental trade where it is sometimes referred to as 'blue tiger piranha' Following Fink and Macaht can be distinguished from other members of the genus by the following combination of characters: body shape deep and rhomboid; head robust, snout blunt; eye large; mouth moderate, jaw projecting; 1-3 ontogeneticlly var...

This species was described from a single specimen and included in the genus Leporinus until 2011 at which point the holotype was examined and recognised as corresponding to the fish described as Synaptolaemus cingulatus (Myers & Fernández-Yépez, 1950).

T. stellatus is superficially similar to its only congener T. securis, but can immediately be identified by the presence (vs. absence) of a prominent dark spot in the dorsal-fin. It is sometimes traded as 'platinum hatchetfish'. The genus Thoracocharax was originally erected by Fowler in 1906 as a subgenus of Gasteropelecus, but was elevated to generic status by Weitzman (1960).

Known only from the rio Uaupés system in Brazil with type locality 'brook emptying into Igarape Yavuari River, tributary of River Uaupés, upper Negro River basin, 0°14'31"N, 68°03'48"W, Amazonas, Brazil'. The full extent of its range is unclear but additional populations may exist.

The genus Acarichthys remains monotypic and was resdescribed by Kullander (1986) who characterised it by the following: lack of epibranchial lobe; comparatively few (12-14)rays; pelvic fins with relatively broad tips (branches of the first ray are equal in length or the inner is slightly longer); possession of a single supraneural plus 14-15 vertebrae (these characters taken as a combination); no caudal extensions to swim bladder; no caudal ribs. Its current taxonomic position is based largel...

This is the type species of the genus Aequidens and has the widest distribution of any member species. It exists in various colour forms depending on locality with variants from Ecuador and Peru being particularly sought after since they develop striking red (Ecuador) or orange (Peru) colouration on the lower part of the jaw, head and anterior portion of the belly whereas those from Brazil tend to have an overall grey/blue/green colouration, for example. Despite its type status it's long...

This species is assigned the codes A220, A221 and A222 under the DATZ 'A' number system with these referring to similar-looking, possibly conspecific, populations. These differ in some aspects of colour pattern, particularly the orientation of the caudal-fin markings which may be horizontal, vertical, or somewhere inbetween. One population displays an orange colouration on the belly and is som...

It's known by various vernacular names including 'Pirá-pacu', 'Pira-pucu' or 'Diente de cao' (central Amazon), 'Bicuda' or 'Uena' (rio Tocantins), 'Bicuda' (rio Tapajós), 'Aguejeta' or 'Picua' (Venezuela), and 'Moruwi' or 'Pirapoko' (Guyana). The entire dorsal-fin base is located anteriorly to a vertical through the anal-fin origin and this character distinguishes it from all other ctenolucids except B. lucius and B. xyrekes.

This species is largely unsuitable for the home aquarium given its eventual size and natural behaviour, and we know of only a handful of private aquarists with the facilities required to house it long-term. Nonetheless juveniles and subadults are sometimes available in the trade although often misidentified as the congener B. maculata.

This species can be told apart from the very similar-looking congener B. filamentosum by its smaller adult size (B. filamentosum can grow to almost 3 m in length), shorter maxillary barbels (never extending beyond base of adipose fin (vs. extending beyond base of adipose fin), moderately-forked with lobes of equal size (vs. deeply-forked caudal fin with upper lobe usually longer than the lower) and body col...

In the Amazon region it is only specimens larger than around 160 cm and werighing in excess of 50 kg that are referred to as 'Piraíba' with the name 'filhote' normally applied to smaller individuals. Other vernacular names include 'Salton catfish', 'Kumakuma'; and 'tiger antenna catfish'; with members of the genus often referred to collectively as 'goliath catfishes'.

Brachyplatystoma spp. are distinguished from all other catfishes by two synapomorphies. The first comprises several morphological characters relating to the skull, specifically that the mandibular suspensorium (that which connects the lower jaw bone to the skull) is greatly expanded mediodorsally to form a large plate approaching the parasphenoid bone, with the hyomandibula and metapterygoid similarly enlarged.

Type locality is given as 'Small tributary of the upper Rio Negro on the equator near São Gabriel da Cachoeira, Brazil', and this species is apparently highly endemic there. Some sources state that it also occurs in the rio Uaupés (known as 'Vaupés' in Colombia), a major tributary of the Negro, but we've been unable to obtain confirmation thus far.

C. amandajanea is rare in the aquarium trade and appears to be variable in colour pattern to an extent, with some individuals posssessing relatively larger dark spots on the body, for example. Unfortunately diagnostic characters cannot be provided since we've been unable to obtain the type description, and little has been written about this species since it was published.

This species is among the more popular Corydoras in the aquarium hobby and is widely available. It may also be referred to as 'arched cory'. There exist a number of similar-looking congeners, particularly C. urucu (Britto et al., 2009), described from the rio Urucu in Coari municipality, Amazonas state, Brazil, and C. narcissus from the rio Purus. The latter appears to have also been traded as C. sp. 'super arcuatus longnose' while a larg...

This species is among a number of congeners native to the rio Negro region to possess a colour pattern with an oblique dark bar running along the dorsal surface of the body. This unofficial group also includes C. burgessi, C. davidsandsi, C. duplicareus, C. imitator, C. melini, and C. serratus, and among these C. duplicareus is most easily-confused with C. adolfoi.

Vernacular names in Brazil include 'Cachorra' or 'Pirandirá', although these are also applied to congeners. It can be told apart from all congeners by the following combination of characters: head and body silvery with dark dorsal surface; an elongate dark blotch posterior to the opercle; dorsal, caudal and anal-fin rays reddish to orange proximally with some individual variation in intensity and tonality; adipose fin dark, with diffuse black pigmentation.

Has been collected from habitats containing clear, soft, acidic, tea-coloured blackwater, most typically among leaf litter or submerged vegetation in very shallow (10-50 cm depth) water along the margins of streams and other minor tributaries. At a village called El Niñal close to the mouth of the rio Pasimoni in the Casiquiare drainage pH was...

This species is relatively rare in the aquarium trade. It can be differentiated from all congeners by a combination of possessing ctenoid (vs. cycloid) scales on the sides of the head plus lacking a dark spot at the caudal-fin base.

Given its eventual size and natural behaviour this species is largely unsuitable for the home aquarium, and we know of only a handful of private aquarists with the facilities required to house it long-term. Unfortunately juveniles are readily available in the trade, although the scarcity of privately-maintained adults would suggest that most fail to reach their potential.

R. vulpinus is the most widely-distributed member of the family Cynodontidae. Type locality is given simply as 'Brazilian rivers', but this species is currently understood to be distributed in the Amazon basin from the Río Ucayali system in Peru, eastward as far as the rio Xingu in Brazil, plus the rio Tocantins and Rio Capim basins. It's also known from the Río Orinoco ba...

Acestridium dichromum