Pangio piperata KOTTELAT & LIM, 1993

Etymology

piperata: based on the Latin Piper, meaning ‘peppered’, in allusion to the finely speckled colour pattern.

Classification

Order: Cypriniformes Family: Cobitidae

Distribution

Known from the states of Terengganu, Panang and Johor in Peninsular Malaysia, southern (peninsular) Thailand, Riau Province in Sumatra and the Rajang river drainage in Sarawak state, Malaysia (Borneo).

Type locality is ‘Stream at about kilometer 6 on Kuala Brang to Kuala Terengganu road, Terengganu, Malaysia, 6°04’25″N, 103°03’20″E’.

Populations from Thailand and Malaysia were found to group apart from each other in molecular phylogenetic analyses and there may be more than a single species involved despite a lack of morphological differences (Bohlen et al. 2011).

Habitat

Most commonly found in shallow, slow-moving sections of forest streams or other calm habitats such as swamps, oxbows, and backwaters.

Many such environments are associated with ancient peat swamps and contain black water although it’s also found in clear waters which may or may not be tannin-stained to some extent.

Such habitats are typically shaded from the sun by marginal vegetation and the dense tree canopy above.

The water generally has a negligible dissolved mineral content, is poorly buffered and pH can be as low as 3.0 or 4.0 due to the gradual release of tannins and organic acids from decaying plant material.

Depending on locality the substrate may be composed of peat, mud or sand with the fish typically abundant in piles of leaf litter.

In the Rajang river basin sympatric species include Cyclocheilichthys apogon, C. repasson, Garra borneensis, Osteochilus hasseltii, Paracrossochilus vittatus, Rasbora argyrotaenia, R. dusonensis, R. kottelati, R. sarawakensis, Trigonopoma pauciperforatum, Sundadanio margarition, ‘Puntius‘ johorensis, ‘P.‘ kuchingensis, ‘P.‘ pentazona, Pangio anguillaris, P. semicincta, Syncrossus hymenophysa, several Gastromyzon, Homaloptera and Nemacheilus spp., Betta akarensis, Sphaerichthys osphromenoides, and Carinotetraodon salivator.

Maximum Standard Length

50 – 60 mm.

Aquarium SizeTop ↑

An aquarium with base measurements of at least 45 ∗ 30 cm or equivalent is recommended.

Maintenance

Use a soft, sandy substrate since this species likes to dig and tends to spend some of its time completely buried. When coarser gravel is used it may become stressed or damage itself, and feeding behaviour can be inhibited.

A few driftwood roots and branches, placed in such a way that plenty of shady spots are formed, can be used to add structure to the display and addition of dried leaf litter would provide additional cover and aid in simulating natural conditions.

Fairly dim lighting is also preferable and aquatic plants from genera such as Microsorum, Taxiphyllum, and Cryptocoryne spp. can also be added.

Gentle filtration providing a little surface agitation is adequate and high flow rates best avoided. Ensure that small specimens are unable to enter filter intakes and cover the tank well as most loaches do jump at times, especially when introduced to a new environment.

Water Conditions

Temperature: 21 – 26 °C

pH: 4.0 – 7.5

Hardness: 0 – 143 ppm

Diet

Chiefly a micropredator sifting mouthfuls of substrate through the mouth and gills from which insect larvae, small crustaceans and suchlike are extracted with a proportion of the natural diet also likely to comprise organic detritus and plant material from the gut contents of prey.

In the aquarium it will accept sinking dried foods but should also be offered regular meals of live and frozen Daphnia, Artemia, bloodworm, micro worm, grindal worm, etc.

Behaviour and CompatibilityTop ↑

Pangio 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.

In nature they’re often found in large aggregations and in captivity will often pack themselves into a single nook, cranny or cave when at rest, so a group of at least 5-6 specimens should be the minimum purchased.

Small, peaceful species from similar environments such as Boraras, Sundadanio, smaller Rasbora, Trichopsis, Sphaerichthys, Kottelatlimia, etc., constitute the best tankmates.

Some sand-dwelling loaches from the family Nemacheilidae are also suitable but proper research is essential as some can be excessively competitive, territorial or otherwise aggressive.

Sexual Dimorphism

Adult females are typically heavier-bodied and a little larger then males, while in mature males the first pectoral-fin ray is branched and thickened

Reproduction

Unrecorded.

NotesTop ↑

This species is exported occasionally, most often as bycatch among shipments of similar-looking congeners.

It’s included in the P. shelfordii group of closely-related species and can be distinguished from other members by the following combination of characters: relatively slender body depth (fitting 9.0 – 10.6 times in SL); lack of nasal barbels; base body colouration yellowish brown and peppered with small dark spots forming a rough stripe along the lateral line; in some specimens a series of dark saddle-shaped markings running along the dorsal surface; 46-49 vertebrae; emarginate caudal-fin; black marking at base of caudal-fin.

Some Sumatran and Bornean populations of the highly variable P. shelfordii superficially resemble P. piperata which can cause issues with identification as the two often occur together.

In general however the colour pattern in P. piperata is plainer than that of P. shelfordii and they differ in vertebral counts (mode 47 vs. 50, respectively).

The pectoral fins in male P. piperata are also proportionally longer being approximately twice as long as those in females vs. slightly longer in P. shelfordii.

Kottelat and Lim (1993) suggested that the P. shelfordii group represents one of four such assemblages within the genus alongside the P. anguillaris, P. kuhlii and P. oblonga groups.

This unofficial system was followed until Bohlen et al. (2011) published a molecular phylogenetic analysis including 18 recognised species plus a number of undescribed ones.

Their results suggest the existence of three, rather than four, major lineages within the genus; the P. anguillaris and P. shelfordii groups represent two of them with Kottelat and Lim’s P. kuhlii and P. oblonga groups together forming the third.

P. shelfordii group members are separated from those of the P. kuhlii-oblonga and P. anguillaris groups by possession of a pair of labial ‘barbels’ on the lower lip, a dark bar at the base of the caudal-fin, several rows of spots on the caudal-fin and a relatively slim caudal peduncle.

They currently include P. atactos, P. incognito, P. muraeniformis, P. piperata, P. shelfordii and P. superba.

Pangio is among the most speciose cobitid genera and widespread throughout South and Southeast Asia with species diversity thought to be considerably greater than currently recognised.

Pangio species are often generically referred to as ‘kuhli’ or ‘coolie’ loaches in the aquarium hobby, the latter a variation of the former which was itself derived from the surname of German naturalist Heinrich Kuhl (1797-1821). Ichthyologists tend to refer to them as ‘eel loaches’.

They’re distinguished from other cobitids by their long, slender body shape, relatively high number of vertebrae and the position of the dorsal-fin which is situated well behind the origin of the pelvic fins (vs. in front of, above or only slightly behind).

Several described members were previously included in the genus Acanthophthalmus which Kottelat (1987) demonstrated to be a syonym of Cobitis, and he chose the replacement name Pangio in preference to its simultaneous synonym Apua (Blyth, 1860).

Myers (1929) placed P. anguillaris as type species of Cobitophis, a grouping containing the very elongate species, while Perugia (1892) originally described P. doriae in the genus Eucirrhichthys. The former was synonymised with Acanthophthalmus by Nalbant (1963) and the latter by Roberts (1989).

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 Pangio was found to be more closely affiliated with Acantopsis, Acanthopsoides and Kottelatlimia than Lepidocephalichthys as had been previously hypothesised.

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. Bohlen, J., V, Šlechtová, H. H. Tan and R. Britz, 2011 - Molecular Phylogenetics and Evolution 61(3): 854-865
   Phylogeny of the Southeast Asian freshwater fish genus Pangio (Cypriniformes; Cobitidae).
2. Britz, R. and J. Maclaine, 2007 - Ichthyological Exploration of Freshwaters 18(1): 17-30
   A review of the eel-loaches, genus Pangio, from Myanmar (Teleostei: Cypriniformes: Cobitidae).
3. Britz, R. and M. Kottelat, 2010 - Ichthyological Exploration of Freshwaters 20(4): 317-376
   Pangio longimanus, a miniature species of eel-loach from central Laos (Teleostei: Cypriniformes: Cobitidae).
4. Burridge, M. E., 1992 - Copeia 1992(1): 172-186
   Systematics of the Acanthophthalmus kuhlii complex (Teleostei: Cobitidae), with the description of a new species from Sarawak and Brunei.
5. Hadiaty, R. K. and M. Kottelat, 2009 - Zootaxa 2171: 65-68
   Pangio lidi, a new species of loach from eastern Borneo, Indonesia.
6. Kottelat, M., 2012 - Raffles Bulletin of Zoology Supplement 26: 1-199
   Conspectus cobitidum: an inventory of the loaches of the world (Teleostei: Cypriniformes: Cobitoidei).
7. Kottelat, M. and K. K. P. Lim, 1993 - Raffles Bulletin of Zoology 41(2): 203-249
   A review of the eel-loaches of the genus Pangio (Teleostei: Cobitidae) from the Malay Peninsula, with descriptions of six new species.
8. Ng, H. H. and H.-H. Tan. 1999 - Zoological Studies 38(3): 350-366
   The fishes of the Endau drainage, Peninsular Malaysia with descriptions of two new species of catfishes (Teleostei: Akysidae, Bagridae).
9. Parenti, L. R. and K. K. P. Lim, 2005 - Raffles Bulletin of Zoology Supplement 13: 175-208.
   Fishes of the Rajang Basin, Sarawak, Malaysia.
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.
11. 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).
12. 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.
13. 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.