Nemachilichthys rueppelli (SYKES, 1839)

SynonymsTop ↑

Nemacheilus shimogensis (Narayan Rao, 1920); Noemacheilus shimogensis (Narayan Rao, 1920); Cobitis rueppelli Sykes, 1839; Cobitis rupelli Sykes, 1839; Noemacheilus ruppelli Sykes, 1839; Noemacheilus rupelli Sykes, 1839.

Etymology

Nemacheilus: from the Greek nēma, meaning ‘thread’ or ‘filament’, cheilos, meaning ‘lip’ and ichthys, meaning ‘fish’.

rueppelli: named to honour Ruppell; the umlaut over the “u” requires “ue” in the spelling.  Sykes (1840) wrote “I have dedicated this beautiful little fish to Ruppell…” with an umlaut.

Classification

Order: Cypriniformes Family: Nemacheilidae

Distribution

Nemachilichthys rueppelli is currently known only from the upper reaches of the east-flowing Krishna River system in the Western Ghats. In particular, the species is reported from seven rivers, Indrayani (Dahanukar et al. 2012), Mula-Mutha, Nira, Krishna, Koyna, Hiranyakeshi and Tunga (Keskar et al., 2015).

Sykes (1839) wrote “Found in the Beema river at Taimbournee and Mota Mola near Puna.”

The Tunga originates in the Western Ghats mountain range and merges with the Bhadra at the town of Koodli before flowing eastwards as the Tungabhadra, one of the most polluted rivers in the country.  The Tungabhadra is itself a tributary of the Krishna River which it joins in Andhra Pradesh state.

This species is now unlikely to occur lower than the confluence of Tunga and Bhadra though records are limited and the only information we have is that specimens collected for the aquarium trade derive from Shimoga district, central Karnataka (A. Rao, pers. comm.).

Habitat

According to Keskar et al. (2015), this species inhabits moderate to fast-flowing streams and rivers. It is often found associated with aquatic vegetation and the submerged roots of riparian vegetation. The species is usually found on the stream or river bed. Preferred substrates include mud, silt, pebbles, small rocks and boulders.  Syntopic species include Cyprinidae: Garra mullya (Sykes), Devario aequipinnatus (McClelland), Rasbora daniconius (Hamilton) and Pethia sp.; Nemacheilidae: Nemacheilus anguilla Annandale, Paracanthocobitis mooreh (Sykes); Cobitidae:
Lepidocephalichthys thermalis (Valenciennes), Gobiidae: Glossogobius giuris (Hamilton) and Mastacembelidae: Mastacembelus armatus (Lacepède).

Water flow rate, depth, and turbidity are highly seasonal and all three increase considerably during the annual monsoons.

One habitat, the Chippalgudda Fish Sanctuary, is a short, officially-protected stretch of the Tunga in southern Shimoga district. The substrate is composed of sand, gravel and granite boulders, there is a steep embankment on the western shore and at one point the river forms a deep pool.

At Chippalgudda this species occurs sympatrically with Barilius bendelisis, Rasbora daniconius, Tor khudree, and Nemacheilus anguilla plus unspecified species of Devario, ‘Puntius‘, Mastacembelus, Parambassis, and Channa.

Maximum Standard Length

70 – 85 mm.

Aquarium SizeTop ↑

An aquarium with a base measuring 90 ∗ 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: 20 – 25 °C

pH: 7.0 – 7.5. Does not seem to appreciate acidic conditions.

Hardness: 36 – 215 ppm

Diet

The bulk of the natural diet is likely to comprise small insects, worms, crustaceans and other zooplankton with only relatively small amounts of plant matter consumed, mostly via the stomach contents of prey items.

Gut content revealed insect parts with higher frequency, followed by ostracods, with relatively low
frequency of plant matter and diatoms (based on 12 unregistered unsexed specimens from Mula-Mutha River at Yerawada, Koyna River at Patan and Nira River at Bhor) (Keskar et al., 2015).

In the aquarium they will accept dried foods of a suitable size but should not be fed these on an exclusive basis. 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 like Gastromyzon, Pseudogastromyzon, Beaufortia, and Sewellia plus benthic cyprinids such as Crossocheilus and Garra species.

Some similarly-shaped relatives such as Acanthocobitis, Schistura and certain other Nemacheilus 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

Bãnãrescu and Nalbant (1995) state that males do not possess a suborbital flap, breeding tubercules or thickened pectoral-fin rays as seen in some related genera, but that the genders can be separated by patterning with males possessing 14-16 well-defined bars on the body compared to 11-14 indistinct bars in females.

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

Reproduction

Unrecorded.

NotesTop ↑

The genus Nemachilichthys was erected by Day (1878) for the type species Cobitis rueppeli Sykes, 1839, and has subsequent to 1920 been comprised of two described species, N. rueppelli (Sykes, 1839) and N. shimogensis Narayan Rao (1920).  In his description, Narayan Rao did not distinguish N. shimogensis from N. rueppelli though both were described as occurring in the Krishna River system.

Several authors considered N. shimogensis to be valid but others regarded it as synonymous with N. rueppelli.  Kottelat (2012) noted that while Bănărescu & Nalbant (1995: 448) considered the two species as distinct, no proper comparison has been published.  Kottelat also pointed out the confusion that exists with respect to the supposed holotype and parotypes of Narayan Rao, along with the apparent inaccuracy of some of the figures in Sykes (1841), concluding that “this can be solved only by examination of topotypes of both nominal species.”

Keskar et al. (2015) examined topotypes of both nominal species using molecular and morphological analyses and concluded that they are conspecific.  “Our genetic and morphometric analysis suggests that the two nominal species are in fact the same and the marginal differences seen in the genetic markers and multivariate morphometric analysis are the result of
geographical separation of populations.”

According to Bãnãrescu and Nalbant (1995) the genus is defined by a combination of characters as follows: elongate, slightly compressed, almost cylindrical body; almost completely scales except the breast, belly and a narrow area between the anal-fin and anus; eyes relatively large compared to other nemacheilids; pointed snout; anus located ‘some distance’ anterior to anal-fin; dorsal-fin located in middle of body with 10-11 branched rays; distal edge of dorsal-fin notched; caudal-fin deeply forked with pointed lobes; adipose crest absent; lateral line complete or almost complete; lips moderately furrowed with median process and 2-4 pairs of grooves on upper lip; processus dentiformis moderate with no corresponding incision on lower jaw; intestine short with single loop; posterior chamber of air bladder capsule rudimentary.

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. Sykes, W. H., 1841 - Transactions of the Zoological Society of London 2: 349-378
   On the fishes of the Dukhun.
2. Bãnãrescu, 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. Keskar, A., P. Kumkar, U. Katwate, A. Ali, R. Raghavan and N. Dahanukar, 2015 - Zootaxa 4059 (no. 3): 555-568
   Redescription of Nemachilichthys rueppelli, a senior synonym of N. shimogensis (Teleostei: Nemacheilidae).
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. Narayan Rao, C. R., 1920 - Annals and Magazine of Natural History (Series 9) v. 6 (no. 31): 45-64
   Some new species of cyprinoid fish from Mysore.
7. Rema Devi, K. and T. J. Indra, 2009(?) - Zoological Survey of India.
   Checklist of the Native Freshwater Fishes of India.
8. Sykes, W.H., 1840 - Annals of Natural History, or Magazine of Zoology, Botany, and Geology v. 4 (no. 21): 54-62
   On the fishes of the Deccan.
9. 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).
10. 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.