Xingu

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...

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.

Known only from the lower Amazon river basin, and possibly restricted to the Xingu and Tocantins watersheds. Type locality is ' Rio Santa Teresa, a western tributary of upper Rio Tocantins, Goiaz State, Brazil', referring to what is now known as Goiás state, central Brazil.

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 The grouping remains poorly-studied with the last major revision having been conducted by Watson (1990) in his unpublished dissertation, in which A. inermis was included under the currently synonymous name A. brevifilis.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...

A somehwhat odd-looking species with a distinctive wide head and overall flattened profile. Unfortunately this fish is not the easiest fish to keep alive in the aquarium since it requires rather specialised conditions and is often in poor condition post-import. As a juvenile, it often sports a pattern of light spots on the body, leading to confusion with the similarly shaped L255 species.In A. ranunculus, these spots fade as the fish mature,...

A somewhat odd-looking species with a distinctive wide head and overall flattened profile. Unfortunately this fish is not the easiest fish to keep alive in the aquarium since it requires rather specialised conditions and is often in poor condition post-import.

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.

Prior to description this species was traded under the DATZ code L047 or the alternative vernacular name 'magnum pleco'. It can be distinguished from congeners by a combination of the following characters: presence of a broad, light-coloured (usually yellowish) distal band on the dorsal and caudal fins throughout life, slightly reduced in adults. The only other member of the genus to possess such bands is B. xanthellus but in that species they are reduced to small markings at the fin tips in adults, and the body is covered in pale, normally yellowish, spots.

It remains unconfirmed as to whether this fish represents a colour form of B. xanthellus or not since its DATZ code number of L081 is not referred to in the description paper whereas all other codes for 'gold nugget' plecos, i.e., L018, L085, L177 plus the 'Das Aquarium' code LDA060 are mentioned. In addition, one of the specimens in our images was apparently collected at São Félix do Xingu which is significantl...

Prior to description in 2011 this species was traded under the DATZ code numbers L018, L085, L077 and 'Das Aquarium' code LDA060, while a very similar-looking fish from the lower rio Xingu which has been assigned the code L081 may also represent a form of B. xanthellus but is not mentioned in the description paper. B. xanthellus can be distinguished from congeners by a combination of the following...

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.

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 relatively rare in the hobby but sometimes available from specialist retailers or private breeders. Though described in 1991 it was first collected much earlier and misidentified by Gosse (1976) as G. surinamensis. It's one of just five Geophagus species not to be included in the nominal G. surinamensis 'group' of closely-related species within the genus along with G. gottwaldi, G. grammepareius, G. harreri an...

Collected from the rio Xingu downstream and in the vicinity of Belo Monte, Pará state, northern Brazil. The majority of its natural habitat is likely to be severely degraded in the near future due to ongoing construction of the Belo Monte dam.

This unidentified species possesses a highly variable colour pattern with the pale, randomly-arranged spots and blotches on the body ranging in colour from whitish to yellowish to rusty orange depending on the specimen. It's regularly confused with similar-looking relativ...

One of the most enigmatic species in the hobby, this incredible little catfish must rank amongst the most stunning freshwater species known. In the late 1990s and the early part of this century you could buy one of these for as little as twenty pounds. However in 2004, the Brazilian government banned the exportation of the species amid apparent concerns over the exploitation of wild stocks. As yet, the conservation status of the fish has not been confirmed by any scientific proof with the only e...

This species is a popular aquarium fish and is bred on a commercial basis in several countries, with a selectively-bred albino form also available. Wild specimens are rarely collected due to the low price of the farmed fish, but the origin of the commercial strain is questionable. The species was considered endemic to the rio Tapajós basin, but in the early 1990s fish appearing identical to the aquarium form were photographed in the...

Widely-distributed throughout the Amazon, Orinoco, Essequibo, and Tocantins river systems in Brazil, Peru, Bolivia, Ecuador, Colombia, Venezuela, and Guyana. Type locality is 'Rio Cupai [= Rio Cupari], Rio Tapajós basin, Amazon River drainage, Pará State, Brazil'.

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 species was described from Suriname but no specific locality was given. It's currently accepted to occur throughout much of the Amazon river system in Brazil, Peru and Bolivia with additional records from coastal drainages of Guyana, Suriname and French Guiana plus the island of Trinidad (Trinidad and Tobago).

Famed as a rapacious predator capable of rapidly stripping flesh from bone and a danger to any animal entering its native waters, P. nattereri is among the most notorious freshwater fishes in the world. As a result, displays featuring this “bloodthirsty” creature are found in most public aquaria, grisly Hollywood movies have been released, and the species has become popular in the aquarium trade. Little of this infamy is based on factual evidence, however.

The precise extent of this species' range is unclear. The majority of records pertain to the lower rio Xingu basin in the state of Pará, northern Brazil, including middle and lower reaches of its major tributary the rio Iriri, although the type locality is in Mato Grosso state several hundred kilometres upstream. There also exist a handful of records from the rio Jamanxim (a major affluent of the rio Tapajós which drain...

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).

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...

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.

H. armatus should probably not be considered a home aquarium subject at all given its eventual size and migratory natural behaviour. Unfortunately, juveniles are seen for sale quite regularly, most often without adequate information regarding their long-term care, and it's common to see them being maintained in medium-sized aquaria with no possibility of achieving their potential.

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.

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...

This species was known as L. sp. 'Buckelkopf' in the aquarium hobby prior to publication of its official description. It's distinguished from all congeners by possessing 7-8 dorsal-fin rays (vs. 9–10 in L. dorsigera, L. fulvipinnis and L. thayeri, 8–9 in L. curviceps and L. flamannellus, and 9–11 in L. flavilabris).