Schistura devdevi (HORA, 1935)

Saddleback Loach

SynonymsTop ↑

Noemacheilus devdevi Hora, 1935; Nemacheilus devdevi (Hora, 1935)

Etymology

Schistura: from the Greek schizein, meaning ‘to divide’, and oura, meaning ‘tail’, in reference to the caudal-fin shape of many species.

Classification

Order: Cypriniformes Family: Nemacheilidae

Distribution

Type locality is ‘Eastern Himalayas; small streams below Darjeeling and Sikkim, India’, and this species is only known with certainty from upland parts of Assam, Sikkim, Arunachal Pradesh and West Bengal states in northern India.

Records from Nepal apparently require confirmation while it may also occur in Bhutan.

The specimens pictured here were collected from the Dooars (aka Duars) region of West Bengal state, northern India.

The Dooars are the floodplains and foothills of the eastern Himalayas around Bhutan, comprising the plains of Darjeeling District, the whole of Jalpaiguri District, the northern part of Cooch Behar District in West Bengal and the districts of Dhubri, Kokrajhar, Barpeta, Goalpara and Bongaigaon in Assam state.

Habitat

Presumably inhabits smaller, well-oxygenated streams and tributaries with clean, flowing water and substrates of gravel, rocks and boulders.

Maintenance

Should not prove difficult to maintain under the correct conditions. We strongly recommend keeping it in a tank designed to resemble a flowing stream or river with a substrate of variably-sized rocks, sand, fine gravel, and some water-worn boulders.

This can be further furnished with driftwood branches arranged to form a network of nooks, crannies, and shaded spots, thus providing broken lines of sight.

While the majority of aquatic plants will fail to thrive in such surroundings hardy types such as Microsorum, Bolbitis, or Anubias spp. can be grown attached to the décor.

Though torrent-like conditions are unnecessary it does best if there is a high proportion of dissolved oxygen and some water movement in the tank meaning power filter(s), additional powerhead(s), or airstone(s) should be employed as necessary.

Like many fishes that naturally inhabit running water it’s intolerant to accumulation of organic pollutants and requires spotless water in order to thrive, meaning weekly water changes of 30-50% tank volume should be considered routine.

Water Conditions

Temperature: 15 – 22 °C

pH: 6.5 – 8.0

Hardness: 36 – 215 ppm

Diet

Schistura species are omnivorous although the bulk of their diet consists of small insects, worms, crustaceans, and other zooplankton with only relatively small amounts of plant matter and other organic detritus consumed.

In the aquarium they will accept dried foods of a suitable size but should not be fed these exclusively. Daily meals of small live and frozen fare such as Daphnia, Artemia, bloodworm, etc., will result in the best colouration and condition.

Behaviour and CompatibilityTop ↑

Unlikely to prove aggressive and should be suitable for a community provided tankmates are selected with care and proper research.

Fishes which inhabit similar biotopes in nature, especially those which swim in open water such as Danio, Devario, Pethia, Puntius, and Rasbora spp. perhaps constitute the best options, and one or two schools can make a visible difference to the confidence of benthic species.

NotesTop ↑

This species has been collected for the aquarium trade, albeit in limited quantities, and is sometimes referred to as ‘firefly loach’.

Unfortunately we’ve been unable to obtain its diagnosis thus far.

Schistura is the most species-rich genus among nemacheilid loaches with some 190 members and it continues to grow with over 100 having been described since 1990.

It may represent a polyphyletic lineage and is often arranged into a number of loosely-defined species ‘groups’, some of which are quite dissimilar to one another.

Among these are an assemblage in which some or all of the body bars are vertically split and another which exhibit reductions in body size (adult size <50 mm SL), the number of pelvic and pectoral-fin rays and often the number of caudal-fin rays and lateral line length, for example.

Some species, such as S. geisleri, also appear to be unrelated to any of the others.

Most inhabit flowing streams or areas close to waterfalls where there naturally exist high concentrations of dissolved oxygen, and a handful are troglobytic, i.e., cave-dwelling, in existence. The latter have reduced pigmentation and are completely blind in many cases.

Schistura spp. are distinguished from other nemacheilids by a combination of morphological characters which include: a moderately arched mouth which is 2-3.5 times wider than it is long; a median ‘interruption’ in the lower lip which does not form two lateral triangular pads and can vary from smooth to furrowed in texture; diverse colour pattern but usually dark with relatively regular bars; usually a black bar at the caudal-fin base which can be broken into two spots or smaller bars; one or two black markings along the base of the dorsal-fin; lack of acuminate scales on the caudal peduncle; caudal-fin shape variable from truncate to forked but usually emarginate; presence or absence of a median notch in the lower jaw; clear sexual dimorphism in some species.

The family Nemacheilidae is widely-distributed across most of Eurasia with the Indian subcontinent, Southeast Asia and China representing particular centres of species diversity.

References

1. Bănărescu, P. M. and T. T. Nalbant, 1995 - Travaux du Muséum d'Histoire Naturelle 'Grigore Antipa' 35: 429-495
   A generical classification of Nemacheilinae with description of two new genera (Teleostei: Cypriniformes: Cobitidae).
2. Kottelat, M., 1990 - Verlag Dr. Friedrich Pfeil, München: 1-262
   Indochinese nemacheilines. A revision of nemacheiline loaches (Pisces: Cypriniformes) of Thailand, Burma, Laos, Cambodia and southern Viet Nam.
3. Kottelat, M., 2012 - Raffles Bulletin of Zoology Supplement 26: 1-199
   Conspectus cobitidum: an inventory of the loaches of the world (Teleostei: Cypriniformes: Cobitoidei).
4. Tang, Q., H. Liu, R. Mayden, and B. Xiong, 2006 - Molecular Phylogenetics and Evolution 39(2): 347-357
   Comparison of evolutionary rates in the mitochondrial DNA cytochrome b gene and control region and their implications for phylogeny of the Cobitoidea (Teleostei: Cypriniformes).
5. Šlechtová, V., J. Bohlen and H. H. Tan, 2007 - Molecular Phylogenetics and Evolution 44(3): 1358-1365
   Families of Cobitoidea (Teleostei; Cypriniformes) as revealed from nuclear genetic data and the position of the mysterious genera Barbucca, Psilorhynchus, Serpenticobitis and Vaillantella.