Aborichthys sp. 'AR02'

Aborichthys: named for the Abor Hills in the state of Arunachal Pradesh, northeast India, in combination with the Greek ichthýs (Gr. ἰχθύς), meaning 'fish'.

Known only from the Raidak I River basin which drains western Bhutan before flowing through the Indian state of West Bengal (Jalpaiguri and Cooch Behar Districts) and merging with the Brahmaputra in northern Bangladesh. The only records we have refer to Indian localities so the full extent of its distribution remains unclear.

Apparently inhabits shallow, swiftly-flowing stretches of water with substrates of gravel and small rocks. Aquatic plants are not a feature although submerged surfaces are often coated in a rich biofilm composed of algae, diatoms and other microorganisms.

Other species inhabiting the Raidak I include Acanthocobitis botia, Schistura scaturigina, Amblyceps mangois, A. apangi, Badis blosyrus, B. sp. cf. kanabos and Microphis deocata.

A group will need a tank with base dimensions measuring upwards of 45 ∗ 30 cm18 ∗ 12 in.

Not difficult to maintain under the correct conditions - we strongly recommend keeping it in a tank designed to resemble a flowing stream/river with a substrate of variably-sized rocks, sand, fine gravel and some large water-worn boulders. This can be further furnished with driftwood branches arranged to form a network of nooks, crannies and shaded spots for this inquisitive species to explore.

Since Aborichthys species like to dig decorative items are best placed directly onto the tank base before the substrate is added.

Like many fishes that naturally inhabit running water it´s intolerant to accumulation of organic pollutants and requires spotless water in order to thrive. It also does best if there is a high proportion of dissolved oxygen and decent water movement in the tank so a powerful external filter/powerhead or two should be added.

While the majority of aquatic plants will fail to thrive in such surroundings hardy types such as Java fern, Bolbitis or Anubias spp. can be grown attached to the décor.

The bulk of its natural diet probably consists of insect larvae, worms, crustaceans and other zooplankton. In the aquarium it will accept dried foods but should also be offered regular meals of small live and frozen fare such as Daphnia, Artemia, bloodworm, etc.

Like many nemacheilids it's an aggressive feeder with a highly-developed sense of taste and the addition of food to the tank often results in a frenzy of activity which can stress slower-moving fishes.

Not especially aggressive but remains largely unsuitable for the 'general' community aquarium due to its specialised requirements. Certainly slow-moving/long-finned species should be omitted because they're likely to struggle with the necessary level of water movement and may end up with nipped fins or be outcompeted at feeding times.

Placid bottom-dwellers such as Corydoras or Pangio species are also best avoided. More suitable are many Danio, Devario, Rasbora and Garra species, as well as gobies from genera such as Rhinogobius, Sicyopterus and Stiphodon or catfishes like Glyptothorax, Akysis and Oreoglanis species.

Many loaches from the family Nemacheilidae and most from Balitoridae are also suitable although squabbles may occur with the former group in particular. Research your choices before purchase in order to be sure.

As far as conspecifics are concerned its perhaps most accurately described as 'loosely sociable' so best kept in groups upwards of six specimens. This will allow you to observe some amusing interactions, and though aggressive behaviour isn't uncommon it shouldn't become problematic in a well-structured set-up.

Adult females should be noticeably fuller-bodied and slightly larger than males; other differences are unreported.

Unreported in aquaria.

This fish occasionally turns up as a contaminant in shipments of A. sp. 'AR01'. The latter is usually traded as A. elongatus but that species appears endemic to higher altitude waters of the Brahmaputra drainage in Darjeeling District which borders Jalpaiguri to the north east. These flow down from the Sivalik Hills whereas the Raidak I originates in Bhutan.

Five species of Aborichthys have been officially described to date but this one appears to represent an undescribed species. It can be told apart from others in the genus by its small adult size and patterning, particularly the relatively wide dark vertical bars which extend the length of the body, and single reddish bar in the caudal-fin. We've listed it as A. sp. 'AR02' after Andrew Rao who contributed invaluable information regarding its origin.

Following Kottelat (1990) the genus is characterised by the following features: "elongate body with uniform depth from nape to caudal fin base; anus situated close behind pelvic girdle; pectoral fin rays not produced and not reaching half the way to base of pelvic fin; pelvic fin origin in front of dorsal fin; rounded caudal fin; 7½ branched dorsal rays; colour pattern consisting of oblique narrow stripes directed downwards backwards; a black spot at upper extremity of base of caudal fin; tail marked with concentric rings".

The family Nemacheilidae is widely-distributed across most of Eurasia with the Indian subcontinent, Southeast Asia and China representing particular centres of species diversity. It was first proposed as a genetically distinct grouping in 2006, and according to current thinking contains over 30 genera of which the most well-known in the aquarium trade are Aborichthys, Acanthocobitis, Barbatula, Mesonoemacheilus, Nemacheilus, Physoschistura, Schistura and Yunnanilus.

These were previously considered members of the family Balitoridae, subfamily Nemacheilinae, but phylogenetic studies have revealed that though closely related Balitorid and Nemacheilid loaches did not evolve from the same common ancestor and represent separate genetic lineages. The revised Balitoridae numbers over 30 genera including some popular aquarium subjects such as Annamia, Beaufortia, Gastromyzon, Homaloptera, Liniparhomaloptera, Pseudogastromyzon, Sewellia, Sinogastromyzon and Vanmanenia species.