Nemacheilus ornatus KOTTELAT, 1990

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

Known only from the Tapi river drainage in Surat Thani province, southern Thailand with type locality ‘Lake Sonkphan, Khlong Sok at Ban Khlong Sok, 8°49’N, 98°35’E, Tapi River basin, Surat Thani Province, Thailand’.

The Tapi originates in neighbouring Nakhon Si Thammarat province but there are no reports of this species occurring there.

Habitat

Said to occur in shallow riffles with substrates of small pebbles and clear, moderately-flowing water.

At one locality in the Tapi basin in Khlong Sok sub-district, Surat Thani, syntopic species included Acanthocobitis zonalternans, Schistura geisleri, Homaloptera smithi, H. ogilviei, Amblyceps mangois and Akysis hendricksoni.

Maximum Standard Length

40 – 45 mm.

Aquarium SizeTop ↑

An aquarium with base dimensions of 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: 6.0 – 7.5

Hardness: 36 – 215 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

Males possess a suborbital flap, and the first four branched pectoral-fin rays are thickened with 3-4 rows of tubercules on the upper surface. These may become thicker/greater in number respectively when the fish are in breeding condition.

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

Reproduction

Unknown in aquaria.

NotesTop ↑

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.

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. 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.
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. Freyhof, J. and D. V. Serov, 2001 - Ichthyological Exploration of Freshwaters 12(2): 133-191
   Nemacheiline loaches from Central Vietnam with descriptions of a new genus and 14 new species (Cypriniformes: Balitoridae).
4. Kottelat, M., 2012 - Raffles Bulletin of Zoology Supplement 26: 1-199
   Conspectus cobitidum: an inventory of the loaches of the world (Teleostei: Cypriniformes: Cobitoidei).
5. 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.
6. 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).
7. 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.