Nemacheilus saravacensis BOULENGER, 1894

SynonymsTop ↑

Nemachilus saravacensis Boulenger, 1894

Etymology

Nemacheilus: from the Greek nēma, meaning ‘thread’ or ‘filament’ and cheilos, meaning ‘lip’ in reference to the furrowed lip in members of this genus.

Classification

Order: Cypriniformes Family: Nemacheilidae

Distribution

Native to the island of Borneo where it’s been recorded from various drainages in the Malaysian state of Sarawak and neighbouring Indonesian province Kalimantan Barat (West Kalimantan).

Similar-looking fishes have been collected further north in Sabah state (Malaysia) but remain unidentified. Type locality is ‘Senah, Sarawak state, Borneo, East Malaysia’.

Habitat

Images depict clear, tea-coloured forest streams with dense marginal vegetation and substrates of sand, small rocks and pebbles.

It’s also known from environments with sandy substrate and organic debris in the form of submerged roots, branches and leaf litter.

The water in such habitats is typified by low mineral hardness and pH. Sympatric species in nature include ‘Puntius‘ kuchingensis, Trigonopoma pauciperforatum, Betta lehi, Acanthopsoides, and Pangio spp.

Maximum Standard Length

Unconfirmed but at least 40 – 50 mm.

Aquarium SizeTop ↑

An aquarium with a base measuring 60 ∗ 30 cm or more is recommended.

Maintenance

Not 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: 23 – 26 °C

pH: 4.5 – 7.0

Hardness: 18 – 179 ppm

Diet

Nemacheilus 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 consumed, mostly via the stomach contents of prey items.

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 ↑

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 rheophilic loaches from genera such as Gastromyzon, Pseudogastromyzon, Beaufortia, and Sewellia, plus benthic cyprinids like Crossocheilus and Garra species.

Some similarly-shaped relatives such as other Nemacheilus, Acanthocobitis, and Schistura spp. are excessively territorial or otherwise aggressive, although a combination may work in larger aquaria.

This species is peaceful with conspecifics and seems to appreciate being maintained in a group so the purchase of four or more specimens is highly recommended.

Sexual Dimorphism

Mature males possess a suborbital flap, rows of tubercules on the dorsal surface of the pectoral fins and a degree of tuberculation on the caudal peduncle.

Adult females are likely to be slightly larger and heavier-bodied than males.

Reproduction

Unrecorded.

NotesTop ↑

This species is rare in the aquarium hobby and may only have appeared as bycatch among shipments of other species to date.

It’s characterised by body patterning consisting of 13-17 irregularly-arranged dark blotches along the lateral line and a further 13-17 saddle-like markings across the dorsal surface.

In some specimens/populations the dorsal and lateral markings are connected. Other features include possession of (usually) 16 branched caudal-fin rays, 9-10½ branched dorsal-fin rays and positioning of the anterior nostril at the ‘extremity of an obliquely-cut tube with pointed tip’ (Hadiaty and Kottelat, 2010).

Following Kottelat (1990) the genus Nemacheilus is characterised by a combination of characters as follows: elongate body; complete lateral line; presence of enlarged scales above and below the lateral line in some species; caudal-fin forked to deeply forked with enlarged upper lobe; large eye; small, strongly arched mouth; lips usually thin; usually no median interruption in upper lip; upper jaw with processus dentiformis (a tooth-like projection); no median notch in lower jaw; long barbels; males usually with suborbital flap, pectoral-fin rays 2-6 thickened and with rows of tubercules.

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. Boulenger, G. A., 1894 - Annals and Magazine of Natural History (Series 6) v. 13(75): 245-251
   Descriptions of new freshwater fishes from Borneo.
2. Bănărescu, P. M. and T. T. Nalbant, 1995 - Travaux du Museum d'Histoire Naturelle 'Grigore Antipa' 35: 429-495
   A generical classification of Nemacheilinae with description of two new genera (Teleostei: Cypriniformes: Cobitidae).
3. Hadiaty, R. K. and M. Kottelat., 2010 - Zootaxa 2557: 39-48
   Nemacheilus marang, a new loach (Teleostei: Nemacheilidae) from Sangkulirang karst, eastern Borneo.
4. Kottelat, M., 1990 - Verlag Dr. Friedrich Pfeil, München, Germany: 1-262
   Indochinese nemacheilines. A revision of nemacheiline loaches (Pisces: Cypriniformes) of Thailand, Burma, Laos, Cambodia and southern Viet Nam.
5. Kottelat, M., 2012 - Raffles Bulletin of Zoology Supplement 26: 1-199
   Conspectus cobitidum: an inventory of the loaches of the world (Teleostei: Cypriniformes: Cobitoidei).
6. Kottelat, M., 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.
7. Kottelat, M. and E. Widjanarti, 2005 - Raffles Bulletin of Zoology Supplement 13: 139-173
   The fishes of Danau Sentarum National Park and the Kapuas Lakes area, Kalimantan Barat, Indonesia.
8. Parenti, L. R. and K. K. P. Lim, 2005 - Raffles Bulletin of Zoology Supplement 13: 175-208
   Fishes of the Rajang Basin, Sarawak, Malaysia.
9. Tan, H. H. and M. Kottelat, 2009 - Ichthyological Exploration of Freshwaters 20(1): 13-69
   The fishes of the Batang Hari drainage, Sumatra, with description of six new species.
10. 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).
11. Šlechtová, V., J. Bohlena 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.