The type locality was a fast-flowing, shallow (50 – 80 cm deep) river between 5-10 metres in width with a substrate of gravel and large rocks. PH was measured at 7.7 and the habitat was unshaded with on…

This species is still considered a member of the genus Nemacheilus by some sources, but it was reclassified and placed in Acanthocobitis by Grant (2008).

Acanthocobitis sinuata, generally considered a junior synonym of A. mooreh (Kottelat, 2012b), also appears distinct and differs in geographical distribution plus number of dorsal-fin rays (2-3/9-10 in A. mooreh vs. 2/8-9 in A. sinuata) and some aspects of colour pattern.

A. sinuata is currently considered a synonym of A. mooreh by most authorities.

This appears attributable to a lack of recent study since the two differ in distribution plu…

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.

Inhabits freshwater swamps and associated streams, typically shaded from the sun by dense riparian vegetation. The water is normally clear or lightly stained with tannins, and the fish found in water less than a metre deep alongside related species including Betta edithae, B. miniopinna, and B. fusca. PH has been measured to range between 4.9-5.5.

Known only from a handful of localities in Bangkok, Samut Sakhon, Samut Songkhram and Samut Prakan provinces in central Thailand, all of which lie on the coast of the Gulf of Thailand.

Most habitats are in close proximity to Bangkok, which continues to expand rapidly, are considered under extreme threat, and recent surveys have failed to confirm that the fish is still present in Samut Songkhram and Samut Prakan.