Barilius canarensis (JERDON, 1849)

SynonymsTop ↑

Opsarius canarensis Jerdon, 1849

Etymology

Barilius: from barila, a vernacular Bengali name for the species B. barila, the type species.

canarensis: named for the Canara/Kanara region in Karnataka and Kerala states, southern India, to which this species is endemic.

Classification

Order: Cypriniformes Family: Cyprinidae

Distribution

Probably restricted to southern parts of Karnataka state and northern Kerala state in southwestern India. Following its redescription in 2015 (see ‘Notes’) it is known with certainty only from the Netravathi and Tungabhadra river systems in Karnataka although it is thought to occur elsewhere.

Type locality is ‘Canara, southern India’, which corresponds to a coastal region of approximately 300 km in length covering several districts of Karnataka and Kerala.

Habitat

Inhabits well-oxygenated, low-to-medium gradient, moderate to fast-flowing rivers and streams with substrates of gravel, cobbles, larger boulders and exposed bedrock.

Many such habitats are being polluted by domestic and industrial waste or degraded by introduction of exotic species and large-scale sand mining operations.

Korkanhalla stream is the type locality of Psilorhynchus tenura Arunachalam and Muralidharan, 2008, and an upper tributary of the Tunga river system flowing through Khudremukh National Park at around 650 m AMSL.

It has a mixed gravel/cobble susbstrate and B. canarensis was also recorded there with sympatric species including Parambassis ranga, Garra mullya, G. bicornuta, Osteochilichthys nashii, Dawkinsia arulius, Puntius sahyadriensis (though the stream is outside the distribution range normally quoted for this species), Rasbora daniconius, Salmophasia boopis, Botia striata, Balitora mysorensis, Schistura semiarmata, Glyptothorax madraspatanum and Mystus keletius.

Maximum Standard Length

110 – 130 mm.

Aquarium SizeTop ↑

Requires a large aquarium with minimum surface area of 150 ∗ 60 cm or equivalent.

Maintenance

The aquarium should ideally be designed to resemble a flowing stream or river with a substrate of variably-sized rocks, sand, fine gravel, and some larger water-worn boulders. This can be further furnished with driftwood roots and branches if you wish but be sure to leave plenty of open swimming space.

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

This species is intolerant to the accumulation of organic wastes and requires spotless water at all times in order to thrive. It also does best if there is a high proportion of dissolved oxygen and moderate degree of water movement meaning external filters, powerheads, airstones, etc., should be employed as necessary.

As stable water conditions are obligatory for its well-being this fish should never be added to biologically-immature aquaria, and weekly water changes of 30-50% aquarium volume should be considered mandatory. A tightly-fitting cover is also essential as Barilius spp. are prodigious jumpers.

Water Conditions

Temperature: 18 – 26 °C

pH: 6.0 – 7.5

Hardness: 36 – 179 ppm

Diet

Barilius spp. are predominantly surface-feeders preying on aquatic and terrestrial insects in nature, with some small fishes and benthic invertebrates probably taken as well.

In the aquarium good quality dried products can be offered but should be supplemented with regular meals of live and frozen fare such as chironomid larvae (bloodworm), Artemia, chopped earthworms, etc. Drosophila fruit flies and small crickets are also suitable provided they are gut-loaded prior to use.

Behaviour and CompatibilityTop ↑

Unsuitable for the general community due to its environmental requirements, and likely to outcompete or intimidate slow-moving and less bold species at meal times since it is an extremely fast swimmer and vigorous feeder. Much smaller fishes should also be omitted as they may be predated upon.

The best tankmates are similarly-sized, robust, pelagic cyprinids such as Dawkinsia, other Barilius or larger Devario and Rasbora spp. while bottom-dwellers could consist of Garra, Crossocheilus, Botia and Schistura spp., for example. Many characids and loricariid catfishes should also work well, but be sure to perform thorough research before purchase.

Although gregarious by nature this is a shoaling rather than schooling species which develops a distinct pecking order and therefore should always be maintained in a group of five or more individuals. If only two or three are purchased the subdominant fish may be bullied incessantly whereas solitary specimens may become aggressive towards similar-looking species.

Sexual Dimorphism

Adult females are less-brightly-coloured, tend to grow a little larger and are thicker-bodied than males, especially when gravid.

Nuptial males develop breeding tubercules on the head and orange pigmentation in the lower portion of the body.

Reproduction

Spawning can apparently be stimulated by performing large, cool water changes but as far as we know there exist no reports of fry being raised.

NotesTop ↑

In the ornamental trade, this species’ name has historically been applied to the congeners B. ardens and B. malabaricus which were described and revalidated, respectively, in 2015.

B. canarensis was redescribed in the same study (Knight et al., 2015), and can be distinguished from congeners by the following combination of characters: unique colour pattern consisting of two rows of bluish-green markings along the length of the body, the upper comprising 9-13 round or oval spots 1-2 scales high and 1-2 scales wide, and the lower 3–4 smaller spots restricted to the anterior portion of the body; dorsal and anal fins with broad white margins; 5+4+2 teeth on the fifth ceratobranchial; 14-15 predorsal scales; 10½ branched dorsal-fin rays; 13½ branched anal-fin rays; 35-36 + 1 lateral line scales; gill rakers slender and well-defined.

The generic placement of Barilius species has been open to question since Howes (1980) concluded that the Barilius grouping, within which they were included at the time, was not monophyletic and identified two separate lineages. The first group contained B. barila, the type species, plus B. bendelisis, B. radiolatus, B. vagra, and B. shacra, while the second included all other species, and initially these were referred to the subdivisions ‘group i’ and ‘group ii’ within Barilius itself.

The composition of these groups is confusing since in a later work Howes (1983) included B. evezardi and B. modestus in ‘group i’ whilst omitting B. bendelisis, B. radiolatus, and B. shacra without explicitly stating why.

Rainboth (1991) assigned the members of Howe’s ‘group ii’ to the revalidated generic name Opsarius based on the fact it was the oldest available with ‘group i’ species retaining the name Barilius due to the presence of the type species.

This system has been followed by some subsequent authors, e.g., Tang et al. (2010) and Collins et al. (2012) but not gain wider usage until Kottelat (2013), who included all former Barilius from Southeast Asia in Opsarius.

References

1. Jerdon, T. C., 1849 - Madras Journal of Literature and Science 15(2): 302-346
   On the fresh-water fishes of southern India.
2. Arunachalam, M. and M. Muralidharan, 2008 - Raffles Bulletin of Zoology 56(2): 405-414
   Description of a new species of the genus Psilorhynchus (Teleostei: Psilorhynchidae) from a western Ghat stream in southern India.
3. Collins R. A., K. F. Armstrong, R. Meier, Y. Yi, S. D. J. Brown, R. H. Cruickshank, S. Keeling, and C. Johnston, 2012 - PLoS ONE 7(1): e28381
   Barcoding and border biosecurity: identifying cyprinid fishes in the aquarium trade.
4. Howes, G. J., 1980 - Bulletin of the British Museum (Natural History) : Zoology series 37(3): 129-198
   The anatomy, phylogeny and classification of bariliine cyprinid fishes.
5. Knight, J. D. M., A. Rai, R. K. P. d'Souza and B. Vijaykrishnan, 2015 - Zootaxa 3926(3): 396-412
   Barilius ardens (Teleostei: Cyprinidae), a new species from the Western Ghats, India, with redescription of B. malabaricus and B. canarensis.
6. Kottelat, M., 2013 - Raffles Bulletin of Zoology Supplement 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. Liao, T-Y, S. O. Kullander, and F. Fang, 2011 - Journal of Zoological Systematics and Evolutionary Research 49(3): 224-232
   Phylogenetic position of rasborin cyprinids and monophyly of major lineages among the Danioninae, based on morphological characters (Cypriniformes: Cyprinidae).
8. Nath, P., D. Dam, and A. Kumar, 2010 - Records of the Zoological Survey of India 110(3): 19-33
   A New Fish Species of the Genus Barilius (Cyprinidae: Rasborinae) from River Siang, D'Ering Memorial Wildlife Sanctuary, Arunachal Pradesh, India.
9. Tang, K. L., M. K. Agnew, W. J. Chen., M. V. Hirt, T. Sado, L. M. Schneider, J. Freyhof, Z. Sulaiman, E. Swartz, C. Vidthayanon, M. Miya, K. Saitoh, A. M. Simons, R. M. Wood, and R. L. Mayden, 2010 - Molecular Phylogenetics and Evolution 57(1): 189-214
   Systematics of the subfamily Danioninae (Teleostei: Cypriniformes: Cyprinidae).