Botia rostrata GÜNTHER, 1868

SynonymsTop ↑

Botia dayi Hora, 1932; Botia nebulosa Blyth, 1860 (questionable)

Classification

Order: Cypriniformes Family: Botiidae

Distribution

B. rostrata as currently recognised may contain a group of closely-related, but distinct, species. Following Grant, (2007) these are:

B. rostrata Günther, 1868 – Native to the lower Ganges and middle to lower Brahmaputra river basins in northern India and Bangladesh; apparent occurrences in Myanmar and China almost certainly refer to misidentified B. histrionica.

Its precise distribution has always been questionable though, with type locality given simply as ‘Bengal, India, and current knowledge suggesting that in India it occurs in the Mahananda River, West Bengal and Bihar states plus the Garo-Khasi hill range, Meghalaya state (likely including the Simsang, aka Someshwari, and Shella river drainages).

In Bangladesh it probably inhabits tributaries of the Padma (Ganges) and the Surma-Meghna river systems although Grant (2007) notes that some or all of these different populations may turn out to represent distinct species with further work.

B. sp. ‘upper Brahmaputra’ – Recorded from numerous tributary drainages of the middle to upper Brahmaputra River in Assam and Arunachal Pradesh states, India including the Khwang, Manas, Kameng (known as Jia Bhoreli in Assam), Subansiri, Dikrong, Pachin, Ranga, Siang, Dibang, Lohit, Noadhing, Buridhing and Tirap rivers.

This appears to be the fish most commonly traded as B. rostrata (see ‘Notes’).

B. sp. ‘ladder’ – A form of unknown origin which is seen in the aquarium trade from time-to-time and doesn’t appear to be a result of artificial hybridisation (see ‘Reproduction’).

Habitat

A riverine species tending to congregate in pools and stiller areas characterised by rocky substrates. It undergoes upstream migrations prior to spawning.

Maximum Standard Length

110 – 120 mm.

Aquarium SizeTop ↑

Base dimensions of 120 ∗ 45 cm or equivalent should be the minimum considered.

Maintenance

All botiids need a well-structured set-up although the actual choice of décor is more-or-less down to personal taste.

A natural-style arrangement could include a substrate of sand or fine gravel with lots of smooth, water-worn rocks and pebbles plus driftwood roots and branches.

Lighting can be relatively subdued and plants able to grow in such conditions like Microsorum pteropus (Java fern), Taxiphyllum barbieri (‘Java’ moss) or Anubias spp. can be added if you wish. These have an added benefit as they can be attached to pieces of décor in such a way as to provide useful shade.

Otherwise be sure to provide plenty of cover as botiids are inquisitive and seems to enjoy exploring their surroundings. Rocks, wood, flower pots and aquarium ornaments can be used in whichever combination to achieve the desired effect.

Bear in mind that they like to squeeze themselves into small gaps and crevices so items with sharp edges should be omitted, and any gaps or holes small enough for a fish to become trapped should be filled in with aquarium-grade silicone sealant. A tightly-fitting cover is also essential as these loaches do jump at times.

Although botiids don’t require turbulent conditions they do best when the water is well-oxygenated with a degree of flow, are intolerant to accumulation of organic wastes and requires spotless water in order to thrive.

For these reasons they should never be introduced to biologically immature set-ups and adapt most readily to stable, mature aquaria. In terms of maintenance weekly water changes of 30-50% tank volume should be considered routine.

Water Conditions

Temperature: 19 – 27 °C. Almost certainly experiences cooler temperatures at certain times of year in nature but for aquarium maintenance somewhere around the middle of this range should suffice.

pH: 6.0 – 7.5

Hardness: 36 – 215 ppm

Diet

While Botia spp. appear to be chiefly carnivorous they will also eat vegetative matter if available, often including soft-leaved aquatic plants. The natural diet comprises aquatic molluscs, insects, worms, and other invertebrates.

They’re largely unfussy feeders but must be offered a varied diet comprising quality dried products, live or frozen bloodworm, Tubifex, Artemia, etc., plus fresh fruit and vegetables such as cucumber, melon, blanched spinach, or courgette.

Home-made foods using a mixture of natural ingredients and bound with gelatin are also highly recommended.

Chopped earthworm can also provide a useful source of protein but should be used sparingly, and while most botiids also prey on aquatic snails though should never be considered the answer to an infestation since they’re not obligate molluscivores.

Once settled into an aquarium they’re bold feeders and often rise into midwater at meal times.

Behaviour and CompatibilityTop ↑

Slow-moving, long-finned species such as ornamental bettas, guppies and many cichlids should also be avoided as trailing fins can be nipped.

More suitable tankmates include peaceful, open water-dwelling cyprinids, while in larger tanks members of Barilius, Luciosoma, Balantiocheilos and Barbonymus become options.

In terms of other bottom-dwellers they will do well alongside most other Botia and in very large tanks, Chromobotia macracanthus. Some cobitid and nemacheilid loaches are also possibilities as are members of Epalzeorhynchos, Crossocheilus and Garra and many catfishes.

As always, thorough research prior to selecting a community of fishes is the best way to avoid problems.

Botia spp. are gregarious, form complex social hierarchies and should be maintained in groups of at least 5 or 6 specimens, preferably 10 or more.

When kept singly they can become withdrawn or aggressive towards similarly-shaped fishes, and if only a pair or trio are purchased the dominant individual may stress the other(s) to the extent that they stop feeding.

That said they seemingly require regular contact with conspecifics, a fact exemplied by a number of behavioural rituals which have been recorded consistently in aquaria (see ‘Notes’).

Sexual Dimorphism

Sexually mature females are normally fuller-bodied than males with a rounded snout, whereas males have an elongated snout with noticeably fleshier lips.

Reproduction

No reports of breeding in private aquaria but some species are mass-produced for the hobby via the use of hormones.

Unfortunately this practice has been taken to a different level in recent years with a number of hybrids appearing on the market, even including an apparent cross between a form of B. histrionica and Chromobotia macracanthus.

NotesTop ↑

Within the nominal species grouping suggested by Grant (2007) almost all B. rostrata sold in the hobby are B. sp. ‘upper Brahmaputra’ with B. rostrata sensu stricto rarely, if ever, available. Trade names include ‘Gangetic loach’, ‘twin-banded loach’ and ‘ladder loach’.

The defining characters of the group are ‘Pattern consisiting of 8-10 black to dark brown body bars that exhibit pale and numerous spots in juveniles, and in adults the bars can anastomose, sometimes completely obscuring the vertical bars on the anterior of the fish. Base colour whitish, or yellowish to gold, sometimes with greenish or bluish tinges.’

Anastomosis of the body pattern is typical in most Botia spp. and can cause problems with identification although members of the B. rostrata group are more likely to be confused with each other than congeners.

B. rostrata – Young specimens usually possess a dark bar under the eye, one on the opercle, another across the snout and 9-10, usually paired vertical bars on the body. These tend to anastomose more in the front portion of the body and in older examples the patterning is reminiscent of B. kubotai.

However that species usually only has 5 body bars and a less-vivid base body colour. The snout and lower fins of adults also tend to develop bright orange/golden colouration. There seem to be less brightly-coloured forms too which may be geographical variants, though none are common in the trade.

B. sp. ‘upper Brahmaputra’ – This form’s appearance is highly variable but juvenile patterning usually consists of 3 dark bars on the head and 9-10 on the body, the latter usually placed in pairs.

The timing and extent of anastomosis of these differs wildly even between individuals of comparable age and size. For example some juvenile specimens can exhibit a total disintegration of the patterning at a young age (~5 cm SL) while others retain the barring to a degree throughout life.

It can be told apart from B. rostrata sensu stricto by its less intense base body colour of beige, yellow or sand, often with a metallic gold/copper sheen, vs. usually yellow to golden with a greenish or blueish sheen. It’s common in the trade and usually available as B. rostrata but sometimes B. geto, a name long-known to represent a junior synonym of B. dario, is used.

B. sp. ‘ladder’ – Very little is known about this fish but in images it appears to possess a distinctive adult body patterning of quite regularly-spaced dark body bars, each containing a vertical row of lighter spots.

The currently-recognised distribution of the genus Botia extends eastwards from the Indus River basin in Pakistan across northern India, then southwards through Myanmar as far as the Salween drainage (Ataran River). This range was previously much larger but modern studies have resulted in various changes to the taxonomy of both family and genus.

The latter is currently defined by the following combination of characters, as given by Kottelat (2004): mental lobe developed in a barbel; fronto-parietal fontanelle narrow; anterior chamber of gas bladder almost entirely covered by bony capsule, posterior chamber large or rather reduced; anterior process of premaxilla entire, not surrounding a cavity; rostral process rather long, with a more or less distinct ridge along inner edge; top of supraethmoid narrow or broad; optic foramen very small; suborbital spine not strongly curved backwards and bifid; head naked.

The family Botiidae has been widely considered a genetically distinct grouping since Nalbant (2002), having previously been considered a subfamily (Botiinae) of the family Cobitidae. Nalbant also moved some previous members of Botia into the new genus Yasuhikotakia based on a number of morphological characters.

Later Kottelat (2004) made further modifications to the taxonomy, raising Chromobotia for B. macracanthus and confirming that species previously included in the genus Hymenophysa should instead be referred to Syncrossus.

The former alteration was based on colour pattern plus some morphological characters and the latter because Hymenophysa not only represents a spelling mistake (McClelland’s original spelling was Hymenphysa) but is a junior synonym of Botia.

More recently Kottelat (2012) erected the genus Ambastaia to accommodate A.nigrolineata and A. sidthimunki, two former members of both  Botia and Yasuhikotakia.

As a result of these works the family Botiidae is thus divided into two tribes within which Botia appears to be the most basal lineage:

Tribe Leptobotiini – Leptobotia, Parabotia, Sinibotia.
Tribe Botiini – Ambastaia, Botia, Chromobotia, Syncrossus, Yasuhikotakia.

Phylogenetic studies by Tang et al. (2005) and Šlechtová et al. (2006) have largely confirmed this system to be correct although the latter disagreed with the placement of Sinibotia, finding it to be more closely related to the tribe Botiini.

Ambastaia nigrolineata and A. sidthimunki were found to be more closely-related to both Sinibotia and Syncrossus than Yasuhikotakia, despite being considered members of the latter at the time. Šlechtová et al. also proposed the use of subfamily names under the following system:

Subfamily Leptobotiinae – Leptobotia, Parabotia.
Subfamily Botiinae – Botia, Chromobotia, Sinibotia, Syncrossus, Yasuhikotakia.

Within these Botia appears to be the basal, i.e., most ancient, lineage and in a more-detailed phylogenetic analysis Šlechtová et al. (2007) confirmed the validity of the family Botiidae with the genera listed above as members rather then being grouped into subfamilies. This more recent, simpler system is the one we currently follow here on SF.

Some behavioural routines exhibited by Botia spp. have been recorded often enough that they’ve been assigned non-scientific terms for ease of reference.

For example during dominance battles (these occur most frequently when the fish have been introduced to a new tank, or new individuals added to an existing group) the protagonists normally lose much of their body patterning and colouration, a phenomenon that’s come to be known as ‘greying out’.

Such displays will sometimes also happen within an established group as individuals seek to improve social ranking but are usually nothing to worry about.

Interestingly some observations suggest that the character of the highest-ranked, or alpha, fish appears to affect that of the whole group though it must be said that scientific studies of botiid loach behaviour are virtually non-existent.

It certainly seems that they display a degree of ‘personality’ with some specimens being naturally bolder or more aggressive than others, for example. The alpha is normally the largest specimen within the group and often female.

‘Shadowing’ is an interesting behaviour in which younger individuals swim flank-to-flank with older, mimicking their every movement. Some keepers report that more than one smaller fish may shadow a larger simultaneously, with even three or four on each side!

The reason for it is unknown; it may relate to a group staying in touch with one another when rivers swell during times of flooding, perhaps reducing drag by swimming ‘in formation’ or having some other communicative function.

It’s been observed in aquaria with both high and low water flow and seems to be habitual to the extent whereby some individuals will shadow other fishes if no conspecifics are present.

Sound also appears to be an important factor in communication since these loaches are able to produce audible clicking sounds, these increasing in volume when the fish are excited. The behavioural aspects of this phenomenon remain largely unstudied but the sounds are thought to be produced by grinding of the pharyngeal (throat) teeth or subocular spines.

A further curiosity is the so-called ‘loachy dance’ which involves an entire group swimming in a constant, restless fashion around the sides of the tank, usually utilising the full length and height.

The reasons for this are unknown and reports as to when it occurs vary but the most common triggers appear to be the addition of food, fresh water or new conspecifics, and it can last anything from a few minutes to a day or more.

Botiids also often settle at peculiar angles, wedged vertically or sideways between items of décor, or even lying flat on the substrate. This is no cause for alarm and appears to be a natural resting behaviour.

Botia spp. also 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 those of larger specimens can break human skin.

Botiids are also susceptible to a condition commonly referred to as ‘skinny disease’ and characterised by a loss of weight. This is especially common in newly-imported specimens and is thought to be caused by a species of the flagellate genus Spironucleus.

It’s treatable although the recommended medication varies depending on country. Hobbyists in the UK tend to use the antibiotic Levamisole and those in the United States Fenbendazole (aka Panacur).

References

1. Günther, A., 1868 - Catalogue of the fishes in the British Museum 7: 1-512
   Catalogue of the Physostomi, containing the families Heteropygii, Cyprinidae, Gonorhynchidae, Hyodontidae, Osteoglossidae, Clupeidae, Chirocentridae, Alepocephalidae, Notopteridae, Halosauridae, in the collection of the British Museum.
2. Grant, S., 2007 - Ichthyofile Number 2: 1-106
   Fishes of the genus Botia Gray, 1831, in the Indian region (Teleostei: Botiidae).
3. Kottelat, M., 2004 - Zootaxa 401: 1-18
   Botia kubotai, a new species of loach (Teleostei: Cobitidae) from the Ataran River basin (Myanmar), with comments on botiinae nomenclature and diagnosis of a new genus.
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. Nalbant, T. T., 2002 - Travaux du Museum d'Histoire Naturelle 'Grigore Antipa' 44: 309-333
   Sixty million years of evolution. Part one: family Botiidae (Pisces: Ostariophysi: Cobitoidea).
6. Nalbant, T. T., 2004 - Travaux du Museum d'Histoire Naturelle 'Grigore Antipa' 47: 269-277
   Hymenphysa, Hymenophysa, Syncrossus, Chromobotia and other problems in the systematics of Botiidae. A reply to Maurice Kottelat.
7. Ng, H. H., 2007 - Zootaxa 1608: 41-49
   Botia udomritthiruji, a new species of botiid loach from southern Myanmar (Teleostei: Botiidae).
8. Tang, Q., B. Xiong, X. Yang and H. Liu, 2005 - Hydrobiologia 544(1): 249-258
   Phylogeny of the East Asian botiine loaches (Cypriniformes, Botiidae) inferred from mitochondrial cytochrome b gene sequences.
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 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.
11. Šlechtová, V., J. Bohlen, J. Freyhof and P. Ráb, 2006 - Molecular Phylogenetics and Evolution 39(2): 529-541
    Molecular phylogeny of the Southeast Asian freshwater fish family Botiidae (Teleostei: Cobitoidea) and the origin of polyploidy in their evolution.