Lepidocephalichthys tomaculum KOTTELAT & LIM, 1992

Etymology

tomaculum: from the Latin tomaculum, meaning ‘sausage’, in reference to the name ‘sausage loach’ which the authors had used to refer to this species prior to its description.

Classification

Order: Cypriniformes Family: Cobitidae

Distribution

Recorded from the states of Selangor, Pahang, Johor and Terengganu in Peninsular Malaysia, with type locality ‘Stream at 34-kilometer mark on road from Sungai Besar to Tonjong Malim, Sungai Bernam basin, Selangor, Malaysia’.

A single collection from Lampung Province, Sumatra was tentatively identified as L. tomaculum by Havird and Page (2010). The authors also state that in some areas where it co-exists with L. hasselti that identification problems arise with some specimens exhibiting characters of both species.

Habitat

Inhabits shallow, slow-moving sections of streams or calm habitats such as freshwater or peat swamps, oxbows, and backwaters. These are typically heavily-vegetated or littered with submerged roots, branches and leaf litter, with substrates composed of soft mud, silt, or peat.

Water clarity and depth vary on a seasonal basis across much of its range, and at certain times of year it probably enters temporarily-flooded zones. Conversely during dry periods some habitats may become stagnant with blooms of macrophytic algae and resultant hypoxia (oxygen depletion).

Under such conditions members of this genus are able to use the intestine as a supplementary breathing organ and have been observed darting to the surface to gulp atmospheric air. Some species have even been recorded to survive periods in moist sand or mud in the absence of water.

Kottelat and Lim (1992) state that this species was collected among submerged beds of Utricularia sp. and grasslike marginal vegetation from a small, shaded stream in the North Selangor peat swamp forest.

This contained slow-moving black water with a pH of 3.5. At other localities it was found in shallow (<0.5 m deep), slow-moving to stagnant, brownish water with a pH of ~5.0 and substrates of mud, leaf litter and other organic debris.

Maximum Standard Length

The largest officially-recorded specimen measured 39.2 mm.

Aquarium SizeTop ↑

Base dimensions of 45 ∗ 30 cm or more are required.

Maintenance

Not difficult to keep but must be provided with a soft, sandy substrate since some of its time will be spent completely buried, or with only eyes protruding. When coarser gravel is used it may become stressed or damage itself trying to dig, and feeding behaviour can be inhibited.

Other décor can include water-worn rocks and driftwood branches and tree roots arranged to form plenty of hiding places and shaded spots – add these prior to the substrate to prevent them being toppled by digging activity.

Lighting can be quite dim unless you intend to grow plants and a few handfuls of leaf litter would complement the natural effect.

As this species hails from sluggish waters high flow rates are best avoided although a degree of oxygenation is recommended.

Ensure that small specimens are unable to enter filter intakes and cover the tank well as most loaches do jump at times, especially when first introduced.

Water Conditions

Temperature: 23 – 29 °C

pH: 3.5 – 7.0

Hardness: 0 – 143 ppm

Diet

Chiefly a micropredator typically sifting mouthfuls of substrate through the gills from which insect larvae, small crustaceans and suchlike are extracted.

In the aquarium it will accept sinking dried foods but should also be offered regular meals of small live and frozen fare such as Daphnia, Artemia, bloodworm, etc.

Behaviour and CompatibilityTop ↑

Lepidocephalichthys spp. are peaceful both with one another and other fishes and there exist no reports of them harming tankmates though they may prey on eggs or fry.

They fare best in the presence of conspecifics and should ideally be kept in a group of 4 or more specimens.

L. tomaculum should do well alongside fishes from similar environments that occupy the upper part of the water column such as Trichopodus, Trichogaster, Trichopsis or certain Danio species.

The presence of these should also make it less timid as the absence of fishes in the upper water column is often used as a signifier for approaching danger in nature.

Sand-dwelling loaches from the families Botiidae, Cobitidae and Nemacheilidae are also suitable but proper research is essential as some can be excessively territorial or otherwise aggressive.

A community based around fishes from its natural waters could include species such as Rasbora cephalotaenia, R. einthovenii, R. kalochroma, Trigonopoma gracile, ‘Puntius‘ johorensis, ‘P.‘ pentazona, Nemacheilus selangoricus, Kottelatlimia pristes, Betta bellica, B. livida, Sphaerichthys osphromenoides and Trichopodus trichopterus.

Sexual Dimorphism

In mature males the pectoral fins are enlarged with fused, thickened innermost (7th and 8th) rays forming a structure known as the lamina circularis.

This generally varies in form depending on species and is present in some other cobitid genera though formed by different rays.

Adult females are typically heavier-bodied and a little larger then males.

Reproduction

Presumably a seasonal spawner in nature but hasn’t been bred in captivity as far as we know.

NotesTop ↑

This species is not traded often but may be available occasionally bycatch among shipments of other species.

It can be told apart from congeners most easily by the following combination of characters: truncate caudal-fin; scaleless patch on top of head; caudal-fin with reticulated patterning, sometimes appearing as a series of thin vertical bars; body reddish brown with darker markings; 3-7 predorsal and 3-6 postdorsal thin, transverse dark bars running across the dorsal surface; relatively deep caudal peduncle meaning body depth is relatively uniform; black spot at base of five uppermost branched caudal-fin rays; lamina circularis in males composed of fused, thickened 7th and 8th pectoral-fin rays forming a small, dorsally-orientated flange in large males only.

The family Cobitidae, often referred to as ‘true’ loaches, is widely-distributed across most of Eurasia with the Indian subcontinent, Southeast Asia and China representing particular centres of species diversity.

Phylogenetic analyses by Tang et al. (2006), Šlechtová et al. (2007) and Šlechtová et al. (2008) revealed that the group constitutes a separate genetic lineage to the family Botiidae (the two were previously grouped together under Cobitidae as subfamilies Cobitinae and Botiinae).

In the most recent study Lepidocephalichthys was not found to be as closely-related to Pangio, Lepidocephalus or Kottelatlimia as previously hypothesised though unfortunately the authors stop short of proposing an alternative theory.

All cobitids possess sharp, motile, sub-ocular spines which are normally concealed within a pouch of skin but erected when an individual is stressed, e.g. if removed from the water. Care is therefore necessary as these can become entangled in aquarium nets and with larger species even break human skin.

References

1. Kottelat, M. and K. K. P. Lim, 1992 - Raffles Bulletin of Zoology 40(2): 201-220
   A synopsis of the Malayan species of Lepidocephalichthys, with descriptions of two new species (Teleostei: Cobitidae).
2. Beamish, F., W., H., R. B. Beamish and S. L.-H. Lim, 2003 - Environmental Biology of Fishes 68(1): 1-13
   Fish Assemblages and Habitat in a Malaysian Blackwater Peat Swamp
3. Havird, J. C. and L. M. Page, 2010 - Copeia 2010(1): 137-159
   A revision of Lepidocephalichthys (Teleostei: Cobitidae) with descriptions of two new species from Thailand, Laos, Vietnam, and Myanmar.
4. Kottelat, M., 2012 - Raffles Bulletin of Zoology Supplement 26: 1-199
   Conspectus cobitidum: an inventory of the loaches of the world (Teleostei: Cypriniformes: Cobitoidei).
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 bibliography of the fishes known to occur in freshwaters, mangroves and estuaries.
6. Kottelat, M. and H. H. Tan, 2008 - Zootaxa 1967: 63-72
   Kottelatlimia hipporhynchos, a new species of loach from southern Borneo (Teleostei: Cobitidae).
7. Mittal, S., P. Mittal and A.K. Mittal, 2004 - Belgian Journal of Zoology 134(1): 9-15
   Operculum of peppered loach, Lepidocephalichthys guntea (Hamilton, 1822) (Cobitidae, Cypriniformes): a scanning electron microscopic and histochemical investigation.
8. Moitra, A., O. N. Singh and J. S. D. Munshi, 1989 - Japanese Journal of Icthyology 36(2): 227-231
   Microanatomy and cytochemistry of the gastro-respiratory tract of an air-breathing cobitidid fish, Lepidocephalichthys guntea.
9. Tang, Q., H. Liu, R. Mayden and B. Xiong, 2006 - Molecular Phylogenetics and Evolution 39(2): 347-357
   Comparison of evolutionary rates in the mitochondrial DNA cytochrome b gene and control region and their implications for phylogeny of the Cobitoidea (Teleostei: Cypriniformes).
10. Šlechtová, V., J. Bohlen and A. Perdices, 2008 - Molecular Phylogenetics and Evolution 47(2): 812-831
    Molecular phylogeny of the freshwater fish family Cobitidae (Cypriniformes: Teleostei): delimitation of genera, mitochondrial introgression and evolution of sexual dimorphism.
11. Šlechtová, V., J. Bohlen and H. H. Tan, 2007 - Molecular Phylogenetics and Evolution 44(3): 1358-1365
    Families of Cobitoidea (Teleostei; Cypriniformes) as revealed from nuclear genetic data and the position of the mysterious genera Barbucca, Psilorhynchus, Serpenticobitis and Vaillantella.