Chagunius baileyi RAINBOTH, 1986

Etymology

Chagunius: derived from chaguni, the vernacular name used for the congener C. chagunio in Bihar state, northern India.

baileyi: named for ichthyologist Reeve M. Bailey (1911-2011).

Classification

Order: Cypriniformes Family: Cyprinidae

Distribution

Endemic to the Salween and Sittaung river basins in Myanmar and western Thailand with the majority of collections having occurred in the area around the border between the countries.

Type locality is ‘Huey Lamao at Ban Mae Lamao, 16°48’N, 98°44’E, Tak Province, Thailand’.

Habitat

Chagunius species inhabit highland rivers and tributaries containing clear water and substrates of rock, gravel, and sand.

They’ve been recorded in areas of rapids as well as sections with moderate current and patches of aquatic vegetation.

Rainboth noted that even juveniles are found in the main channels, as opposed to backwater habitats, but they show a preference for slightly calmer water than adults which can often be found schooling with Tor spp. in faster-flowing zones.

Maximum Standard Length

The largest officially-recorded specimen measured 200 mm.

Aquarium SizeTop ↑

Not a suitable species for smaller aquaria and base dimensions of 180 ∗ 60 cm should be the minimum considered.

Maintenance

Choice of décor is not likely to be as critical as water quality and the amount of open swimming-space provided.

However should you possess the means to both provide and decorate a sufficiently-sized tank for long term care this species would look superb in a set-up designed to resemble a flowing river with a substrate of variably-sized rocks and gravel, some large water-worn boulders and some driftwood branches.

Like many other species that hail from running waters it’s almost certain to react poorly to any accumulation of organic wastes and spotless water with a high proportion of dissolved oxygen and a decent amount of water movement is required in order for it to thrive.

Be sure to fit the tank with a heavy, tightly-fitting cover as larger cyprinids can be quite skittish at times and usually possess a powerful leap.

Water Conditions

Temperature: 18 – 25 °C

pH: 6.0 – 7.5

Hardness: 90 – 357 ppm

Diet

Rainboth examined the stomach contents of numerous specimens and found that younger fish fed mostly on aquatic invertebrates whereas adults contained large amounts of ‘fine sediment’.

Plant material did not appear to be consumed in large quantities and members of the genus are prehaps best described as foraging micropredators.

For it to develop optimum condition it should therefore be offered regular meals of small live and frozen foods such as bloodworm, Daphnia and Artemia along with good quality dried flakes and granules.

Behaviour and CompatibilityTop ↑

C. baileyi is unlikely to prey on tankmates although its adult size dictates that very small species are best omitted, and comparably-sized fishes that inhabit similar environments in nature should make the best companions.

As always when selecting a compatible community of fish proper research is essential in order to avoid problems.

This species is found swimming in loose aggregations in nature and might exhibit shy or skittish behaviour if kept singly or in small numbers.

It’s a shoaling rather than schooling fish which develops a distinct pecking order and the purchase of a group of six or more is recommended if lucky enough to find it on sale in such numbers and possess the space required to house a group.

This will provide a more natural-looking display plus interesting behaviour from the fish as they interact with conspecifics.

It goes without saying that the size of aquarium required to adequately accommodate such a community over anything other than the short term is beyond the reach of most private aquarists.

Sexual Dimorphism

Adult males develop noticeable tubercules on the head while females do not.

Reproduction

Unrecorded.

NotesTop ↑

Members of this genus are rarely-kept in aquaria, with C. baileyi only occasionally available as bycatch among shipments of wild fish from Thailand and Myanmar.

There are currently three species which look almost identical are most easily separated by collection details since their ranges do not overlap in nature; C. chagunio is endemic to the Ganges and Brahmaputra drainages and C. nicholsi to the Ayeyarwady/Irrawaddy.

Morphological differences are few, with C. chagunio possessing more circumferential scales (40, vs. 36 or less) and more circumpeduncular scales (23-25, vs. 18-20) than the other two.

C. baileyi and C. nicholsi can only be told apart by counting the anal scales (4-5 in the former, vs. 2) and the relative size of the eye (slightly larger in C. baileyi).

We’re yet to see images of live C. nicholsi but a further distinguishing characteristic between young C. baileyi and C. chagunio is the presence of red marginal stripes in the caudal-fin of the former, though apparently this colouration is lost as the fish mature.

The distribution of the genus is interesting because these fish occupy the area that geographically separates Indian and Southeast Asia barbs and it’s been theorised that they may represent an evolutionary ‘link’ (Rainboth, 1986).

They exhibit an intriguing morphology that can be described as intermediate between Indian Hypselobarbus and Southeast Asian genera such as Tor in some respects, for example.

References

1. Rainboth, W. J., 1986 - Occasional Papers of the Museum of Zoology University of Michigan 712: 1-17
   Fishes of the Asian Cyprinid Genus Chagunius.
2. Kottelat, M., 2013 - The 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.
3. Smith, H. M., 1938 - Proceedings of the Biological Society of Washington v. 51: 157-158
   Chagunius, a new genus of Asiatic cyprinoid fishes.