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Paracanthocobitis botia (HAMILTON, 1822)

Zipper Loach

SynonymsTop ↑

Cobitis botia Hamilton, 1822; Nemacheilus botia (Hamilton, 1822); Noemacheilus botia (Hamilton, 1822); Cobitis turio Hamilton, 1822; Cobitis bilturio Hamilton, 1822; Cobitis bimucronata McClelland, 1839: Cobitis ocellata McClelland, 1839; Cobitis gibbosa McClelland, 1839; Cobitis monocera McClelland, 1839; Cobites argentata Swainson, 1839; Cobitis arenata Valenciennes, in Jacquemont, 1839; Canthophrys unispina Swainson, 1839; Nemachilus mackenziei Chaudhuri, 1910; Acanthocobitis botia (Hamilton, 1822)


Paracanthocobitis: from the Greek παρά (para), meaning ‘close beside,’ and the genus Acanthocobitis, derived from the Greek  acantho-, meaning ‘thorny’, and kobitis, meaning ‘a kind of sardine’.


Order: Cypriniformes Family: Nemacheilidae


Described from ‘northeastern Bengal’ and formerly considered to have an enormous range extending eastwards from the Indus River basin in Pakistan through northern India, Nepal, Bhutan, Bangladesh, Myanmar, the Chinese province of Yunnan, and into western Thailand, and covering several major river drainages including the Ganges, Irrawaddy,  Salween, and Mae Klong.

Kottelat (2012) considers the former synonyms A. mooreh (Sykes, 1839) from Peninsular India, A. urophthalmus (Günther, 1868) from Sri Lanka, and A. mandalayensis (Rendahl, 1948) from Myanmar to be valid species, while noting that specimens from the Mae Klong drainage previously identified as A. botia are in fact A. pictilis, and that specimens from the Indus, Ganges and Brahmaputra may not all be conspecific.

Singer and Page (2015) give the distribution of P. botia as the mainstem, and possibly tributaries, of the Brahmaputra River, in Assam, India (p. 388).


Habitats vary to some extent and most are  seasonal in nature, e.g., swelling in volume and flowing more rapidly during the annual monsoons.

However in general it shows a preference for stretches of streams and small rivers where leaf litter and other debris collects, areas of open sand or mixed cobbles, rocks, and boulders.

Maximum Standard Length

Normally 80 – 100 mm. Reports of it reaching 152 mm probably refer to misidentified specimens of A. pavonacea.

Aquarium SizeTop ↑

Base dimensions in excess of 75 ∗ 30 cm are sufficient.


Will do well in most larger, well-maintained tanks if plenty of hiding places are provided, and should not harm softer-leaved plants.

However we recommend keeping it in a set-up designed to resemble a slow-moving or marginal section of stream or river with a sandy substrate and perhaps a few water-worn boulders.

This can be decorated with driftwood roots and branches arranged to form some shaded spots, plus a few handfuls of dried beech, oak or Terminalia (Indian Almond) leaves. Aquatic plants such as Microsorum, Bolbitis or Anubias spp. can be grown attached to the décor and bright lighting will promote the growth of aufwuchs which will add to the natural feel.

In this kind of environment the fish will show more natural behaviour and can be maintained alongside other species that enjoy similar conditions (see ‘compatibility’).

Although a high level of water movement isn’t essential it’s also proven to thrive in a mature hill stream-type set-up with a rocky aquascape.

Water Conditions

Temperature: 21 – 26 °C

pH: 6.0 – 7.5

Hardness: 90 – 215 ppm


Chiefly a micropredator feeding on insect larvae and suchlike in nature.  Singer and Page (2015) report that stomach contents examined during their study were larval chironomids and ephemeropterans.

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. A varied diet is the key to maintaining it in the best of health.

Behaviour and CompatibilityTop ↑

Generally peaceful and can be maintained alongside many of the more popular species in the hobby although ideally fishes from from one of its native countries or rivers should be selected.

Most small, peaceful schooling or shoaling cyprinids are excellent choices as are many other loaches such as Lepidocephalichthys and some Nemacheilus spp.

In a hill stream-style set-up it can also be housed with rheophilic loaches such as Gastromyzon, Pseudogastromyzon, Beaufortia and Sewellia spp., but more aggressive nemacheilids, e.g., similarly-sized Schistura spp. are best avoided.

It exists in loose aggregations in nature and can exhibit shy or skittish behaviour if kept singly or in small numbers so buy a group of six or more. You´ll be rewarded with a more natural-looking display plus interesting behaviour from the fish as they interact with conspecifics.

Some specimens have been known to nip the fins of rivals.

Sexual Dimorphism

Adult males are slimmer and have a suborbital slit, visible as a cleft in the skin, extending from below the eye which is absent in females.


As far as we know it’s not bred commercially and all fish available in the trade are probably collected from wild stocks.

There do exist a few reports of fry being found in mature, well-decorated aquaria although the numbers recovered were very small and it seems likely this species eats its eggs given the opportunity.

UK aquarist Mick Wright has had success with the related A. zonalternans so perhaps an upscaled version of his approach would be a good starting point; see the relevant section of that species profile for more information.

NotesTop ↑

P. botia is traded under various names including ‘mottled‘, ‘eyepot’, ‘sand‘ and ‘striped‘ loach. It’s perhaps one of the better choices for those new to keeping nemacheilids being relatively hardy, peaceful and exhibiting some quirky behavioural traits.

The characteristic ocellus, a dark marking at the top of the caudal peduncle that resembles an eye, is thought to have some function in predator distraction and is normally more intense in younger specimens.

Paracanthocobitis botia is distinguished from all other species of Paracanthocobitis by the combination of complete lateral line; suborbital flap in male; no axillary pelvic lobe; small dorsal saddles; 8–10 dark blotches along and just below lateral line; usually 10 and 1/2 dorsal-fin rays; and 12 pectoral-fin rays (Singer and Page, 2015, p. 387).

P. botia can be told apart from congeners by colour pattern comprising dark, saddle-shaped markings forming an irregular pattern along the dorsal surface and upper body, a series of roundish to triangular, non-elongated markings along the lateral line, these often connected to each other, and which may or may not be connected to the saddles.  In other species the saddles and lateral markings tend to be arranged more regularly.

The genus Acanthocobitis was described by Peters (1861) with Acanthocobitis longipinnis designated as the type species.  The placement and status of this species was questioned by several authors beginning with Menon (1987) who considered it a junior synonym of Cobitis botia Hamilton, 1822.  Grant (2007) compared the holotype of A. longipinnis with live specimens of A. botia and found the two species to be easily distinguished.  He noted that A. longipinnis is distinguished from all other Acanthocobitis species including A. botia in having a pointed caudal fin, vertically oriented suborbital flap, slender body, long dorsal fin, anus closer to anal-fin insertion than to pelvic-fin insertion, and greenish colouration.

Grant (2007) considered Acanthocobitis longipinnis to be a junior synonym of A. pavonacea and proposed the subgenus Paracanthocobitis (type species C. zonalternans) to include all other species since he regarded A. pavonacea to be taxonomically unique.  Kottelat (2012a) remarked that the identity of A. longipinnis required verification and later (Kottelat, 2012b) classed Paracanthocobitis as a questionable synonym of Acanthocobitis.

Singer and Page (2015) recognize Paracanthocobitis as a genus, differing from Acanthocobitis as diagnosed by Grant (2007, 2008), although the two genera are most likely sister taxa based on the unique papillated pad on either side of a medial interruption on the lower lip.  Fourteen species including five new species described therein are assigned to Paracanthocobitis, with Acanthocobitis treated as monotypic, containing only A. pavonacea, a species restricted to the Brahmaputra and Ganges river basins of northern India and Bangladesh.  Acanthocobitis longipinnis is considered to be a synonym of A. pavonacea (Grant, 2007); however, the only available specimen of A. longpinnis is the poorly preserved holotype.  Collection of fresh material may show the two forms to be distinguishable from one another.  [Singer and Page, 2015, p. 398]

Paracanthocobitis is distinguished from all other genera in the family by the combination of lower lip with a large papillated pad on either side of a medial interruption; upper lip with 2–5 rows of papillae and continuous with lower lip; conspicuous black spot with white outline (an ocellus) on upper half of caudal-fin base.

Paracanthocobitis is distinguished from Acanthocobitis in having an emarginate or truncate (vs. pointed) caudal fin; 9 and 1/2 –15 and 1/2 (vs. 17 and 1/2 –19 and 1/2) branched dorsal-fin rays; rounded (vs. more triangular-shaped) head in lateral view; horizontally (vs. vertically) oriented suborbital flap or groove; papillated pad on either side of narrow (vs. wide) medial interruption in lower lip; anus closer to pelvic-fin insertion than to anal-fin insertion (vs. closer to anal-fin insertion).  [Singer and Page, 2015, p. 380]

The family Nemacheilidae is widely-distributed across most of Eurasia with the Indian subcontinent, Southeast Asia and China representing particular centres of species diversity.


  1. Grant, S., 2007 - Ichthyofile No. 2: 1-9
    A new subgenus of Acanthocobitis Peters, 1861 (Teleostei: Nemacheilidae).
  2. Grant, S., 2008 - BSSW-Report 20(3): 49-52
    Schmerlen der Gattung Acanthocobitis Peters, 1861.
  3. Kottelat, M., 2012b - Raffles Bulletin of Zoology Supplement 26: 1-199
    Conspectus cobitidum: an inventory of the loaches of the world (Teleostei: Cypriniformes: Cobitoidei).
  4. Kottelat, M., 1990 - Verlag Dr. Friedrich Pfeil, München, Germany: 1-262
    Indochinese nemacheilines. A revision of nemacheiline loaches (Pisces: Cypriniformes) of Thailand, Burma, Laos, Cambodia and southern Viet Nam.
  5. Kottelat, M., 2012a - Zootaxa 3327: 45-52
    Acanthocobitis pictilis, a new species of loach from Myanmar and Thailand (Teleostei: Nemacheilidae).
  6. Kottelat, M., 2013 - Raffles Bulletin of Zoology Supplement No. 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.
  7. Singer, R. A. and L. M. Page, 2015 - Copeia v. 103 (no 2): 378-401
    Revision of the zipper loaches, Acanthocobitis and Paracanthocobitis (Teleostei: Nemacheilidae), with descriptions of five new species.
  8. 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).
  9. Vishwanath, W. and J. Laisram, 2001 - Journal of the Bombay Natural History Society 98(2): 197-216
    Fishes of the subfamily Nemacheilinae Regan (Cypriniformes: Balitoridae) from Manipur.
  10. 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.

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