Crossocheilus cobitis (BLEEKER, 1854)

SynonymsTop ↑

Lobocheilos cobitis Bleeker, 1854; ? Epalzeorhynchos kalliurus Smith, 1945

Etymology

Crossocheilus: from the Ancient Greek κροσσός (krossós), meaning ‘fringe, tassel’, and χείλος (cheílos), meaning ‘lip’, in reference to the barbels on the upper lip in members of this genus.

cobitis: from the Ancient Greek κωβῖτις (kobitis), meaning ‘like a gudgeon’, in reference to this species’ resemblance to certain loaches of the family Cobitidae.

Classification

Order: Cypriniformes Family: Cyprinidae

Distribution

This species is currently accepted to be the most common member of the genus with a wide distribution extending southwards from the Mekong river drainage in Laos, Vietnam, and Thailand to the Greater Sunda Islands of Sumatra, Borneo, and Java, via the Chao Phraya and Mae Klong river systems in central and western Thailand and numerous fluvial systems in Peninsular Malaysia.

Type locality is ‘Padang, Sumatra, Indonesia; Jakarta, Java, Indonesia’.

Habitat

C. cobitis is primarily a lowland species inhabiting the lower reaches of rivers, and is often found in turbid water with muddy substrates where it tends to be collected close to submerged solid objects such as logs, floating houses, and stationary boats.

Maximum Standard Length

45 – 52 mm.

Aquarium SizeTop ↑

Minimum base dimensions of 100 ∗ 30 cm are recommended.

Diet

In nature Crossocheilus species are aufwuchs grazers feeding on algae, diatoms and other phytoplankton, plus associated microorganisms. The use of high-protein foods in the aquarium should therefore be avoided as the fish are unable to metabolise some components efficiently; regular, prolonged consumption can result in excessive deposits of fat and even organ degeneration.

A good quality dried product(s) with added Spirulina or similar is ideal but plenty of fresh vegetable matter should also be included in the diet. Shelled peas, blanched courgette, spinach and chopped fruit all make good additions to the menu. Once settled into the aquarium the fish sometimes ascend into midwater to feed and in a set-up as described above will often be seen browsing the biofilm that tends to form on the rockwork.

NotesTop ↑

Given its wide natural range it seems logical that this species is or has been available in the aquarium hobby, although its correct name may never have been applied. The vast majority of laterally-striped Crossocheilus species entering the ornamental market are traded as ‘Crossocheilus siamensis’, an invalid synonym of Epalzeorhynchos siamensis which is itself a synonym of Crossocheilus oblongus.

That said, it is also likely that C. cobitis represents a group of similar-looking, closely-related species and will be reclassified in the future.

As things stand, it is told apart from congeners by the following combination of characters: two pairs of barbels; a continuous midlateral stripe from the tip of the snout to the base of the caudal-fin, with a conspicuous small blotch at the posterior extremity, faintly marked on the caudal-fin; a faint mark between the anus and the anal-fin origin in juveniles; a narrow mouth.

Members of Crossocheilus are characterised by possessing 8 branched dorsal fin rays, immobile rostral lobes, lacking a dorsal spine and by the fact that the upper and lower lips aren’t connected, the upper being attached to the lower jaw via a thin membrane.

References

1. Bleeker, P., 1854 - Natuurkundig Tijdschrift voor Nederlandsch Indië v. 5: 495-534
   Nieuwe tientallen diagnostische beschrijvingen van nieuwe of weinig bekende vischsoorten van Sumatra.
2. Bănărescu, P. M., 1986 - Travaux du Muséum d'Histoire Naturelle 28: 141-161
   A review of the species of Crossocheilus, Epalzeorhynchos and Paracrossochilus (Pisces, Cyprinidae).
3. 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.
4. Kottelat, M., 2001 - WHT Publications, Colombo: 1-198
   Fishes of Laos.
5. Kottelat, M. and E. Widjanarti, 2005 - The Raffles Bulletin of Zoology Supplement 13: 139-173
   The fishes of Danau Sentarum National Park and the Kapuas Lakes area, Kalimantan Barat, Indonesia.
6. Kottelat, M. and H. H. Tan, 2011 - The Raffles Bulletin of Zoology 59(2): 195-199
   Crossocheilus elegans, a new species of fish from northern Borneo (Teleostei: Cyprinidae).
7. Rainboth, W. J., 1996 - FAO, Rome: 1-265
   Fishes of the Cambodian Mekong. FAO Species Identification Field Guide for Fishery Purposes.
8. Roberts, T. R., 1989 - Memoirs of the California Academy of Sciences No. 14: i-xii + 1-210
   The freshwater fishes of western Borneo (Kalimantan Barat, Indonesia).
9. Su, R.-F., J.-X. Yang and Y.-R. Chen, 2000 - The Raffles Bulletin of Zoology 48(2): 215-221
   A review of the Chinese species of Crossocheilus, with description of a new species (Ostariophysi: Cyprinidae).
10. Tan, H. H. and M. Kottelat, 2009 - Ichthyological Exploration of Freshwaters 20(1): 13-69
    The fishes of the Batang Hari drainage, Sumatra, with description of six new species.