Tapajós

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 The grouping remains poorly-studied with the last major revision having been conducted by Watson (1990) in his unpublished dissertation, in which A. inermis was included under the currently synonymous name A. brevifilis.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

Localities known in the hobby include 'Pastaza', 'Putumayo', 'Requena', 'Río Nanay', 'Rio Napo', 'Maniti', 'Momón', 'Río Tigre', 'Río Ampiyacu', 'Shishita', 'Shushupi', 'Yavari', 'Tefé', 'Manaquiri', 'Lago do Januari', 'Mamori' (often misspelled 'Mamuri'), 'Careiro', 'Manacapuru', 'Juruá', 'Curuaí', and 'Purutu' though we've been unable to find anywhere matching the latter name within the species' known distribution, and in fact several of these names are applied incorrectly on a regular basis.

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.

The genus Baryancistrus can be distinguished from all other loricariids by possession of an enlarged membrane located posteriorly to the last branched dorsal-fin ray. This membrane may or may not reach the supporting structure of the adipose fin and in this way members can be told apart from the genera Oligancistrus, Parancistrus, and Spectracanthicus, in which the dorsal and adipose fins are completely connected, and Hemiancistrus...

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...

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...

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.

There are at least two variants available one of which is often traded as G.sp. 'Araguaia orange head'. This is misleading since both are endemic to the Tapajós drainage (see 'Distribution'), and appears to date back to an error in collection locality when the fish were first exported. The two differ in the extent of orange colouration on the head which extends onto the opercle in G. sp. 'orange head (rio Arapiuns form) but is mostly restricted to the area above the ey...

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...

A similar-looking, larger form from the rio Jarí, which enters the Amazon from the opposite bank a few hundred kilometres downstream from the Tapajós has been assigned the code L411. The two can be told apart relatively easily since in L260 the white vermiculations on the body are significantly finer than in L411, in which the black and white components of the colour pattern are of more-or-less equivalent width.

Its name appears to have been misapplied to similar-looking fishes occurring throughout much of the middle and lower Amazon in Brazil and Colombia, plus the rio Orinoco drainage in Colombia and Venezuela, and coastal systems of the Guianas. Some of these have been described as distinct species (e.g. Hyphessobrycon amapaensis Zarske & Géry 1998; H. eschwartzae García-Alzate, Román-Valencia & Ortega 2013; H. montagi Lima, Couthino & Woziacki 2014), whereas the identity of others remains un...

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...

Choice of décor is not especially critical although it tends to show better colouration when maintained in a well-furnished set-up with live plants and a dark substrate. A natural-looking arrangement might consist of a soft, sandy substrate with wood roots and bran...

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'.

Metynnis lippincottianus is occasionally seen for sale, sometimes under the name of "Silver Dollar". It is easily distinguishable from m. argenteus and m. hypsauchen (which are more commonly sold as Silver Dollars) by its spotted pattern, hence the common name. M. lippincottianus shares a common name with m. maculatus but the two can be distinguished as the spots on m. maculatus are more pronounced. Silver dollars are common and popular fish in the hobby. They are related to piranh...

Native to the central Amazon basin with records existing from the Madeira, Branco, Trombetas, and Tapajós river drainages, plus the Rupununi basin in Guyana. Although an affluent of the rio Essequibo and thus not officially part of the Amazon basin, the latter is connected to the rio Takutu, a tributary of the upper rio Branco, during the annual wet season. Type locality is given by Fowler as 'Rio Madeira about 200 miles east of W. Long. 62°20', Brazil'.

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...

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 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.

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 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).

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.

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.

Native to the lower Amazon river basin in Brazil with some populations exhibiting differences in colour pattern to one another, particularly in respect of the degree of red and blue pigmentation on the body and fins. Type locality is given simply as 'Amazon River, Brazil'. Field observations suggest it to display a pref...

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.

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).