N. binotatus is distinguished from similar-looking congeners such as N. longistriatus and N. ornatus by its unique body patterning consisting very simply of two dark stripes, one running along the dorsal surface and the other from the tip of the snout, through the eye and along the flank.

There are usually 1-3 small, vertically-orientated spots extending above the lateral stripe between the pectoral-fin and dorsal fins. These are su…

Fishes which inhabit similar biotopes in nature constitute the best options, especially peaceful, open water-dwelling cyprinids since the presence of one or two schools can make a visible difference to the confidence of this naturally reclusive loach.

Other possibilities include rheoph…

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…

Among them it’s most similar to I. pumila which was initially described as a subspecies but is now considered distinct. The two are most easily-separated by colour pattern; I. koreensis has 10 or…

It’s most easily told apart from K. brevifasciata, its only congener, by body patterning consisting of dark, vertical bars running along the dorso-ventral part of the body (vs. dark bars running alongside the midventral part of the body), lips with wrinkled surfaces (vs. smooth) and barbels short (vs. long).

Patterning is highly variable depending both within and between populations and the species may comprise an assemblage containing a number of taxa (Kottelat and Lim, 1993; Tan and Kottelat, 2009). For example, those from Singapore and Johor possessing intricate mottling on the dorsal surface while individuals from Terengganu have a series of saddle-like markings either alternating or connecting with the midlateral markings.

Some Sumatran and Bornean populations of the highly variable P. shelfordii superficially resemble P. piperata which can cause issues with identification as the two often occur together. In general however the body patterning in P. piperata is than that of P. shelfordii and they differ in vertebral counts (mode 47 vs. 50, respectively).

It’s included in the P. kuhlii–oblonga group of closely-related species within the genus as per Bohlen et al. (2011) and can be…

Originally known only from Johor and Pahang states, Peninsular Malaysia but since recorded from the Batang Hari river drainage, Sumatra and the Kapuas system, Kalimantan Barat (West Kalimantan) province, Indonesian Borneo. Type locality is ‘Tahan River, Pahang, Malaysia’.

It’s included in the P. kuhlii group of closely-related species and can be distinguished from other members by the following combination of characters: 8-11 very broad, quadrangular, regular dark body bars; orange base body colour; caudal-fin either entirely black or with a large black blotch at the base and a submarginal dark bar or row of spots. The latter feature can be useful in identifying young or newly-imported, undernourished specimens which can…