Tocantins

Despite its patent unsuitability as an aquarium subject attractively-coloured juvenile specimens of this species are traded in quite large numbers, although the scarcity of privately-maintained adults would suggest that most fail to reach their potential. The striking, spotted patterning also disappears as this species matures, and since it also becomes increasingly bellligerent with age it can only be recommended to owners of the largest private aquaria or tropical ponds. There exists an albino...

Despite its patent unsuitability as an aquarium subject attractively-coloured juvenile specimens of this species are traded in quite large numbers, although the scarcity of privately-maintained adults would suggest that most fail to reach their potential. The striking, spotted patterning also disappears as this species matures, and since it also becomes increasingly bellligerent with age it can only be recommended to owners of the largest private aquaria or tropical ponds. There exists an albino...

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...

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 The grouping remains poorly-studied with the last major revision having been conducted by Watson (1990) in his unpublished dissertation, in which A. inermis was included under the currently synonymous name A. brevifilis.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

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.

This species is also known by the alternative vernacular name of 'Zamora woodcat', and is often misidentified as A. thoracatus. The latter is a valid species and very similar to A. coracoideus in that the coracoid bone is exposed ventrally and covered only by a thin layer of integument in both species. The two differ principally in the number of anal fin rays...

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.

This species was formerly included in the genus Brochis alongside C. britskii and C. multiradiatus, and is sometimes referred to as 'common brochis'. Juveniles have a mottled colour pattern and are sometimes traded as 'hi-fin cory' due to their enlarged dorsal-fin. C. splendens can be told apart from other ex-Brochis species by possession of 10-12 dorsal-fin rays...

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.

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 cas...

This species was available in the hobby several years prior to being described, invariably traded as G. sp. aff. altifrons 'Tocantins', G. sp. 'Tocantins' or G. sp. 'rio Areoes'. The latter of these names refers to an Indian reserve named 'Areões' in the rio Das Mortes drainage, a tributary of the Araguaia which itself drains into the Tocantins, and the aquarium specimens in our images have been identified as G. neambi by Dr. Paulo Lucinda, co-describer of the species.

The genus Hypancistrus is diagnosed from all other loricariids by a wide separation between the metapterygoid and lateral ethmoid, presence of a sharply angled adductor palatini crest of the hyomandibula, and no lateral wall in the metapterygoid channel. More useful for aquarists is the fact that in Hypancistrus the dentary teeth are about twice a...

Type locality is 'Rio das Mortes, some 100 km before its confluence with the Braço Maior of the Rio Araguaia (the western border of the Isla do Bananal). State of Mato Grosso.' The das Mortes is a principal tributary of the Araguaia, itself the major affluent of the rio Tocantins within the lower Amazon basin in central and western Brazil, although the full range of H. amandae within the Araguaia system is unclear.

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...

In the aquarium hobby the name Hyphessobrycon stegemanni has frequently been misapplied to a species that has been described as Hemigrammus ataktos Marinho, Dagosta, & Birindelli 2014. The reasons for this confusion are presumably that the two occur sympatrically in the rio Tocantins system and both possess a dark lateral stripe on the body.

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...

This species can be distinguished from all congeners except P. bachi and some specimens of P. furcata by possessing only faint spots and saddles on the body. It can be told apart from P. bachi by possession of narrow (vs. wide) pelvic-fin spines, having the eyes positioned high (vs. low) on the head, and distinctly round (vs. appearing more as a mottling) spots on the body.

Wild specimens are probably omnivorous foragers but with a preference for aquatic invertebrates and suchlike. In the aquarium it does best when offered a varied diet comprising sinking dried foods, frozen Daphnia, mosquito larvae, chironomid larvae (bloodworm), and prawn/shrimp, for, example, plus some fresh fruit, parboiled potato, etc.

Retroculus spp. are unsuitable for the standard community aquarium, and should be maintained in a set-up designed to resemble a flowing river. The substrate should be composed of soft sand mixed with small pebbles if the aim is to breed the fish (see 'Reproduction'). Rocks, boulders, roots, branches, and aquatic plants can also be added, although the la...

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...

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).

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.

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'.

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...

It is distinguished from congeners by the following combination of characters: anal-fin with 6-7 basal pterygiophores and 9 rays (vs. 10-11 rays in C. asellus and C. psittacus; dorsal-fin with 10 bas...

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).

Known only from affluents within the upper rio Tocantins basin draining into the enormous Serra da Mesa hydroelectric reservoir in Goiás state, Brazil. It has been collected from the rios Maranhão, das Almas, Traíras, and Palmerinha/Palmeira(?). Type locality is 'Brazil, Goiás, Rio Tocantins basin, Rio das Almas, tributary of left margin of Rio Maranhão, 14˚37′51.2″S, 49˚1′56.6″W'.