Opsarius dogarsinghi (HORA, 1921)

Manipur Baril

SynonymsTop ↑

Barilius dogarsinghi Hora, 1921

Etymology

Opsarius: apparently from an Ancient Greek word meaning ‘small fish’.

dogarsinghi: named in honour of Sardar Dogar Singh, State Overseer, Manipur, India, who gave Hora “material assistance” in the collection of specimens (including type of this one), and helped arrange survey tours.

Classification

Order: Cypriniformes Family: Cyprinidae

Distribution

The majority of records for ‘B.‘ dogarsinghi are from the Chindwin river system in Manipur and Nagaland states, northeastern India, with a handful of occurrences in Myanmar, and it may be restricted to the Manipur and Yu affluent drainages including their respective major tributaries the Myittha and Lokchao rivers, plus the upper Barak river basin which forms part of the Ganges-Brahmaputra system.

Type locality is ‘Etok stream near Chanderkhong, southern watershed of the Naga Hills, Manipur, Assam’.

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.

Maximum Standard Length

80 – 85 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 Opsarius spp. are prodigious jumpers.

Water Conditions

Temperature: 18 – 24 °C

pH: 6.0 – 7.5

Hardness: 36 – 215 ppm

Diet

Opsarius 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, 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 tubercules on the head and orange pigmentation in the lower portion of the body.

Reproduction

This species has been bred in aquaria (see images), but we have no detailed information at this time.

NotesTop ↑

This species occasionally appears in the ornamental trade under names including ‘Burmese hill trout’ and ‘striped hill trout’.

It can be distinguished from congeners by the following combination of characters: predorsal scales 20; a large dark blotch at the base of the caudal-fin; 38-39 lateral line scales; 8-9 dark blue vertical bars on the body, reaching but not usually extending below lateral line; one pair of short rostral barbels; symphyseal knob absent.

The generic placement of species currently referred to Opsarius 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. Hora, S. L., 1921 - Records of the Indian Museum (Calcutta) 22(pt. 3, no. 19): 165-214
   Fish and fisheries of Manipur with some observations on those of the Naga Hills.
2. Arunkumar, L. and H. Tombi Singh, 2000 - Journal of the Bombay Natural History Society 97(2): 247-252
   Bariliine fishes of Manipur, India, with description of a new species: Barilius lairokensis.
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. 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.
6. 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).
7. 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.
8. Selim, K. and W. Vishwanath, 2002 - Journal of the Bombay Natural History Society 99(2): 267-270
   A new cyprinid fish species of Barilius Hamilton from the Chatrickong River, Manipur, 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).