Lobocheilos rhabdoura (FOWLER, 1934)

SynonymsTop ↑

Tylognathus rhabdoura Fowler, 1934; ? Tylognathus gracilis Fowler, 1937; ? Tylognathus trangensis Fowler, 1939; ? Tylognathus delacouri Pellegrin & Fang, 1940; ? Lobocheilus cornutus Smith, 1945; ? Lobocheilus cheveyi Smith, 1945; ? Lobocheilus thavili Smith, 1945

Etymology

Lobocheilos: from the Ancient Greek λοβός (lobós), meaning ‘lobe’, and χείλος (cheílos), meaning ‘lip’, in reference to the prominent rostral cap in this genus.

rhabdoura: from the Ancient Greek  ῥάβδος (rhábdos), meaning ‘streak, stripe’, and οὐρά (ourá), meaning ‘tail’, in reference to the dark lateral band on the posterior portion of the body, terminating in a blotch on the caudal peduncle.

Classification

Order: Cypriniformes Family: Cyprinidae

Distribution

Native to the Mekong River in Laos, Thailand, Cambodia, and Vietnam, the Dong Nai basin in southern Vietnam, the Chao Phraya and Mae Klong systems in central and western Thailand, and several smaller drainages in peninsular Thailand and northern Peninsular Malaysia.

Type locality is ‘Chieng Mai, North Siam’, corresponding to the Ping River basin, a tributary within the Chao Phraya watershed in Chiang Mai province, northern Thailand.

Habitat

This species is considered to be one of the most abundant species in the massive seasonal migrations of cyprinid fishes that occur in the mainstream Mekong river in December to February and May to July.

Otherwise, it has been recorded in rivers and streams of all sizes down to around 2-3 m in width, mostly with moderate to fast flow and rocky substrates.

Maximum Standard Length

150 – 220 mm.

Aquarium SizeTop ↑

An aquarium with base dimensions of 180 ∗ 60 cm or equivalent should be the smallest considered.

Maintenance

A display arranged to resemble a flowing stream or river, with a substrate of variably-sized, water-worn rocks, sand, fine gravel and perhaps some small boulders, is highly recommended. This can be further furnished with driftwood roots or branches and hardy aquatic plants such as Microsorum, Bolbitis, or Anubias spp., which can be grown attached to items of décor.

Most importantly, the water must be clean and well-oxygenated with turnover preferably in excess of 10 times per hour; additional powerheads and airstones can be employed to achieve the desired flow and oxygenation if necessary. Bright lighting will promote development of a biofilm on solid surfaces, upon which the fish will graze.

Water Conditions

Temperature: 20 – 26 °C

pH: 6.0 – 8.0

Hardness: 36 – 215 ppm

Diet

Lobocheilos species are specialised grazers of periphyton, benthic algae, and other organisms which grow attached to rocks and other solid surfaces, and they typically leave visible scrape marks in places where they have been feeding.

They are by no means herbivorous and should be offered meaty foods such as live or frozen chironomid larvae (bloodworm), Tubifex, Artemia, chopped prawn, etc., along with good quality, sinking dried products, at least some of which should contain a significant proportion of vegetable matter such as Spirulina or similar.

Behaviour and CompatibilityTop ↑

Can be aggressive at times, especially when food is added to the aquarium, and will often actively pursue fishes straying into the vicinity.

The most suitable tankmates are active, peaceful cyprinids since they are normally agile enough to avoid such attacks. Slow-moving or long-finned species should be omitted in the majority of circumstances.

It is not particularly tolerant of conspecifics, especially if space is limited, but normally exists in loose aggregations in the wild and should ideally be maintained in a group.

Sexual Dimorphism

Sexually mature females are deeper-bodied than males, while males possess more extensive tuberculation on the head and snout.

Reproduction

Unreported in aquaria. Wild fish undertake seasonal spawning migrations, moving from the lower Mekong and Tonlé Sap system to the middle portion of the Mekong basin in Laos to spawn.

NotesTop ↑

The majority of Lobocheilos species are endemic to the Greater Sunda Islands of Borneo, Sumatra, and Java, and are uncommon in the aquarium trade, but the widespread Indochinese taxa L. rhabdoura and L. melanotaenia are available on a sporadic basis.

L. rhabdoura can be distinguished from L. melanotaenia by the following combination of characters: body relatively shallow, depth fits 3.7-4.6 times in SL; mouth relatively wide, as wide as head; tubercules on snout relatively large; 10 predorsal scales; 5+28 rakers on anterior side of first gill arch.

Lobocheilos species are considered members of the tribe Labeonini within the putative cyprinid subfamily Cyprininae or simply the subfamily Labeoninae (name varies with author). According to the most recent phylogenetic research, this grouping is further divided into four subtribes; Labeoina, Garraina, Osteochilina, and Semilabeoina (Yang et al., 2012). Among these, it is included in the Osteochilina alongside the genera Epalzeorhynchos, Crossocheilus, Barbichthys, Thynnichthys, Labiobarbus, and Osteochilus, among others.

References

1. Fowler, H. W., 1934 - Proceedings of the Academy of Natural Sciences of Philadelphia v. 86: 67-163
   Zoological results of the third De Schauensee Siamese Expedition, Part I - Fishes.
2. Freyhof, J., D. V. Serov and T. N. Nguyen, 2000 - Bonner Zoologische Beiträge 49(1-4): 93-99
   A preliminary checklist of the freshwater fishes of the River Dong Nai, South Vietnam.
3. Kottelat, M., 2001 - WHT Publications, Colombo: 1-198
   Fishes of Laos.
4. 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.
5. Kottelat, M., 1998 - Ichthyological Exploration of Freshwaters 9(1): 1-128
   Fishes of the Nam Theun and Xe Bangfai basins, Laos, with diagnoses of twenty-two new species (Teleostei: Cyprinidae, Balitoridae, Cobitidae, Coiidae and Odontobutidae).
6. Rainboth, W. J., 1996 - FAO, Rome: 1-265
   FAO species identification field guide for fishery purposes. Fishes of the Cambodian Mekong.
7. Yang, L., M. Arunachalam, T. Sado, B. A. Levin, A. S. Golubtsov, J. Freyhof, J. P. Friel, W-J. Chen, M. V. Hirt, R. Manickam, M. K. Agnew, A. M. Simons, K. Saitoh, M. Miya, R. L. Mayden, and S. He, 2012 - Molecular Phylogenetics and Evolution 65(2): 362-379
   Molecular phylogeny of the cyprinid tribe Labeonini (Teleostei: Cypriniformes).