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 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…

Several Brachyrhamdia species have developed colour patterns that mimic syntopically-occurring Corydoras spp. throughout the life-cycle, and the remainder, including B. meesi, may mimic Otocinclus or smaller Corydoras spp. when juvenile. They’re easily told apart from Corydoras by their significantly longer barbels and lack of scute-like plates on the body.

This rich feeding ground is exploited until the sea water returns, at which point the catfishes begin to migrate upstream in massive numbers, moving up the Amazon and its tributaries. Sexually mature individuals are not normally recorded during these events so they’re thought related to feeding and dispersal rather than spawning. The fish are subject to intensive capture by commercial and artisanal fishing operations during this upstream movement.

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…

Study of B. rousseauxii has revealed that sexually mature adults are found only in the western Amazon, with no mature individual ever recorded east of Manaus despite the intensive commercial fishery operating there. The total distance covered by some populations during migration from the delta was as much as 5500 km, making it the longest known in any freshwater fish species.

Found in a number of habitat-types, though rarely in smaller tributaries, generally preferring deeper, flowing channels through which it travels for considerable distances at certain times of year. Like other large, migratory pimelodids these movements are typically associated with nutrient-rich, white water drainages rather than nutrient-poor black waters.

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…

The form from the rio Içana tends to have more blue markings on the head than that from the Uaupés, while a reddish population apparently collected close to the settlement of Tucana (sometimes mis-spelled ‘Tucano’) on the Uaupés is sometimes traded as A. elizabethae ‘super red’.

Apistogramma is among the most speciose of South American cichlid genera with around 70 species valid at present but many more awaiting description.

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…