Schistura disparizona ZHOU & KOTTELAT, 2005

Etymology

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

disparizona: from the Latin dispar, meaning ‘dissimilar’, and zona, meaning ‘band’, in reference to the colour pattern of this species.

Classification

Order: Cypriniformes Family: Nemacheilidae

Distribution

Known only from the type locality ‘Cangyuan, Nangun River (a Salween River tributary), 0.5 kilometers to Manglai on road from Banhong to Mangku, 23°16.49’N, 99°04.34’E, Yunnan Province, China’.

Habitat

Inhabits shallow, narrow branches of streams with substrates of gravel or stone.

Maximum Standard Length

The largest specimen known measured 96.2 mm.

Aquarium SizeTop ↑

Base dimensions of 120 ∗ 30 cm or equivalent should be the smallest considered.

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: 18 – 25 °C

pH: 6.0 – 8.0

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 ↑

Aquarium behaviour is currently unknown though it certainly appears to be a robust fish and we wouldn’t recommend combining it with slow-moving, long-finned, or very placid tankmates.

Sexual Dimorphism

None has been observed.

Reproduction

Unrecorded.

NotesTop ↑

This species does not appear to have entered the aquarium trade to date.

It can be told apart from congeners by its colour pattern which consists of 8-11 closely-set, narrow dark bars in the anterior part of the body and 5 wider bars in the posterior part. It also possesses prominent dorsal and ventral adipose crests on the caudal peduncle and 9½ branched dorsal-fin rays.

It’s closest relatives in the genus appear to be S. alticrista Kottelat, 1990 and S. callidora Bohlen and Ŝlechtová, 2011, which also possess a well-developed adipose crest on the dorsal midline of the caudal peduncle and 9½ branched dorsal-fin rays (vs. no or low adipose crest and 7½ or 8½ in most other species of Schistura).

S. disparizona differs from S. alticrista by its colour pattern of closely-arranged vertical bars in the anterior portion of the flank with the posterior bars more widely-set  vs. bars and interspaces of equal width on the whole body.

S. callidora shares a colour pattern of narrow, densely-set bars in the anterior part of flank and broader bars and interspaces posteriorly, but it differs from S. disparizona in lacking an adipose crest on the ventral midline of the caudal peduncle, possessing a deeper caudal peduncle (depth 0.8-1.0 times in its length, vs. 0.9-1.4), dark grey or black markings on the top of the head, dorsal and caudal fins (vs. absence), the anterior body bars are as wide or wider than the interspaces (vs. much thinner), the black bar at the caudal-fin base reaches the dorsal midline (vs. does not reach) and it usually has two predorsal saddles (vs 3-5).

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. Zhou, W. and M. Kottelat, 2005 - Raffles Bulletin of Zoology Supplement 13: 17-20
   Schistura disparizona, a new species of loach from Salween drainage in Yunnan (Teleostei: Balitoridae).
2. Bohlen, J. and V. Ŝlechtová, 2011 - Ichthyological Exploration of Freshwaters 22(2): 1-10
   A new genus and two new species of loaches (Teleostei: Nemacheilidae) from Myanmar.
3. 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).
4. Kottelat, 2013, 2013 - Raffles Bulletin of Zoology Supplement No. 27: 1-663
   The fishes of the inland waters of southeast Asia: a catalogue and core bibiography of the fishes known to occur in freshwaters, mangroves and estuaries.
5. 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.
6. Kottelat, M., 2012 - Raffles Bulletin of Zoology Supplement 26: 1-199
   Conspectus cobitidum: an inventory of the loaches of the world (Teleostei: Cypriniformes: Cobitoidei).
7. 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).
8. 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.