The physical appearance of B. almorhae sensu stricto is something of a mystery. No pictures of live specimens appear in any scientific publications we've read and we've been unable to find a certified image of one anywhere meaning it's possibly never been seen in the aquarium trade.
Instead the most commonly available members of the nominal species grouping seem to be B. lohachata, B. sp. 'Kosi' and B. sp. 'Teesta' (see individual notes below), plus the assorted hybrids that have appeared since the turn of the century (Grant, 2007).
The most commonly-used vernacular name of 'yo-yo' loach is derived from the typical body patterning in juveniles of the group, comprising a series of alternating 'i' and 'y' shaped black, grey or brown bars (usually 4-5 of the former, 3 of the latter) which in most specimens appears to form that phrase if one imagines the 'i' bars to form the centre of each 'o'.
As the fish age the bars break up in a process sometimes referred to as anastomosis. B. almorhae group members are further told apart from other Botia spp. by a base body colour of 'whitish, yellow, golden, or very light green' and relatively large adult size of up to 160 mm SL (Grant, 2007).
B. almorhae - The description of this species is very brief and it was not until a year after publication that Gray published a drawing of the holotype with the now synonymous name B. grandi.
It's often been confused with B. birdi and B. lohachata and the latter has been considered a junior synonym by some authors.
Body colouration in juveniles is yellowish with brown 'i' and 'y' markings with 1-3 bands in the dorsal-fin. As the fish age the number of bands in both pectoral and dorsal fins increases and the 'i' and 'y' markings anastomose resulting in a series of highly variable yellow spots. In some adults part of the 'i' and 'y' patterning can remain but this does not appear related to gender (Grant, 2007).
B. birdi - Juvenile colouration is yellow to beige with brown to black 'i' and 'y' markings, whereas in adults the lower portion of the body is yellowish white and the upper darker. The 'i' and 'y' bars do not reach the ventral surface, anastomose up in some specimens and in very large adults can be absent altogether.
The pectoral, anal and ventral fins contain either no markings or 2-3 bands; the dorsal-fin has 2-3 brown to black bands and the caudal 3-4. Chaudhuri (1909) states that the snout in his specimens was reddish post-capture.
This species is very similar in appearance to B. almorhae and Grant (2007) found the only discernible differences to be colour pattern, distribution and the number of vertebrae (27-30 in B. almorhae vs. 30-31 in B. birdi but considered this sufficient to maintain their status as distinct species in the absence of genetic studies.
Although the Indus and Ganges drainages are separated now it's thought the Yamuna River connected the two as little as 4000 years ago so this may explain these species' similarity.
At any rate you're unlikely to see B. birdi on sale given the lack of commercial fish collections in its native rivers and again, verified images of live specimens are almost unheard of.
B. lohachata - The validity of this species has never been fully resolved since it was described using just a single juvenile specimen. Young fish exhibit a gold to silver metallic sheen while adult body is grey to green without sheen. There are typically 3 'y' markings which anastomose or remain unconnected in some individuals of all ages.
The dorsal-fin has 2 or 3 bands (usually 3), the caudal 3-4, the anal 1-2 (usually 1), the ventrals 1-4 (usually increasing in number with age) and the pectoral fins usually 3. Grant (2007) considers it distinct but stresses that confirmation is required, and we think this form definitely has been exported for the aquarium trade.
B. sp. 'Kosi'- This potentially undescribed species tends to possess paler base body colouration and a reduced body depth compared to length than B. almorhae and B. lohachata.
Grant (2007) hypothesises that it may be undescribed since work by Ng and Edds in 2005 proved that catfishes inhabiting different rivers in Nepal (e.g., the Kosi, Narayani, Seti, Ghomti, etc.) and previously considered to represent the same species are in fact different. B. sp. 'Kosi' is available in the trade on an occasional basis.
B. sp. 'Teesta'- Grant (2007) considers this an undescribed species based on it's distribution (Brahmaputra, as opposed to Ganges river basin) and the fact it differs slightly in patterning compared with B. almorhae. This one has also been seen in the hobby.
As currently recognised the 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).
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