It’s a member of the nominal G. surinamensis ‘group’ of closely-related species within the genus and can be identified by a combination of characters including: presence of dark preopercular markings; seven parallel vertical bars on each flank (normally visible only when the fish are stressed, spawning or preserved); vertical bars four and five meet in such a way that they form a ‘Y’ shape; dark lateral spot positioned within the third vertical bar; caudal fin reddish with variable pattern of iridescent blue spots and stripes.

It also occurs in the río Caura on the Guyana Shield plus the Ventauri and Mavaca drainages in the middle and upper Orinoco where it’s also known from some white water, referring to turbidity rather than turbulence, habitats. To the north its distribution appears limited by the Las Majaguas dam on the Río Cojedes, a tributary of the Apure where a probable introduced population inhabits the res…

This species was originally named Nemacheilus masyae but following ICZN rules the spelling was later corrected to N. masyai because it’s named after a man. It can be distinguished from the majority of congeners by body patterning comprising 14-18 short, dark vertical bars on each flank, 12-17 saddle-like markings running along the dorsal surface, a dark spot on the caudal peduncle at the termination of the lateral line and a dark blotch in the lower half of the first few dorsal-fin rays.

Known only from a single cave system (Tham Sai Yok Noi) near the town of Nam Tok Sai Yok Noi, Sai Yok district, Kanchanaburi Province, Thailand. The headwater stream running through the cave is part of the Khwae Noi river basin, itself a tributary of the upper Mae Klong system.

621 metres of the cave system has repor…

It’s a member of the N. selangoricus group of species within the genus, an assemblage first recognised by Hadiaty and Kottelat (2009) and characterised by possession of two rows of horizontally-arran…

This species is only traded occasionally. It’s distinguished from congeners by a combination of characters including: 12-16 dark, irregular, vertical bars on body, usually split vertically; lips without furrows; inco…

Images depict clear, tea-coloured forest streams with dense marginal vegetation and substrates of sand and/or small rocks and pebbles. It’s also known from environments with sandy substrate and organic debris in the form of submerged roots/branches and le…

The similar-looking N. masyai is sometimes traded as N. pallidus, but the two can be told apart by body depth (14.8-19.1 % in N. pallidus vs. 12.6-17.6 % SL in N. masyai), interorbital width (5.7-8.0 % vs. 4.9-6.8 % SL) and the fact that in N. pallidus the dark body bars and saddles are thinner than the light-coloured interspaces between (vs. wider in N. masyai).

This species is distinguished from similar-looking congeners such as N. longistriatus and N. ornatus by its unique colour pattern consisting of a black lateral body stripe with 9-16 vertically-orientated blotches extending along it both above and below, plus an irregular stripe running along the dorsal surface. The anterior lateral blotch is surrounded by lighter pigment, forming an ocellus similar to that seen in N. binotatus.

This species is frequently misidentified as Nemachilichthys rueppelli (Sykes, 1839) but that species was described from close to Pune in Maharashtra state, well over 500 km north of Shimoga. Further, in his description of N. rueppeli Sykes states that the body colour is ‘greenish yellow’ and ‘the lateral line marked with short dark bars’.

Narayan Rao described the colour pattern of…