Tanichthys albonubes LIN, 1932

White Cloud Mountain Minnow

SynonymsTop ↑

Aphyocypris pooni Herre, 1939

Etymology

Tanichthys: named for Chinese boy scout leader Tan Kan Fei, who first collected the type species, plus the Greek ἰχθύς (ichthus), meaning ‘fish’.

albonubes: from the Latin albus, meaning ‘white’, and nubes, meaning ‘cloud’, in reference to the species’ type locality (see ‘Distribution’).

Classification

Order: Cypriniformes Family: Cyprinidae

Distribution

Type locality is ‘White Cloud Mountain, Kwangtung, China’, referring to White Cloud Mountain (also known as Mount Baiyun or Baiyunshan) a few miles north of the city of Guangzhou, Guangdong Province, China and this species is probably restricted to the Pearl River Delta region.

It appears to been extirpated from the ‘mountain’ which is actually a collection of thirty or so peaks and now a popular tourist resort complete with cable car access, hotels and public parks.

Between 1980 and 2001 it was not recorded anywhere at all leading to fears of its extinction but a handful of relict populations have been discovered close to the type locality and at isolated spots in coastal Guangdong province (in the prefecture-level city of Shanwei) and Quang Ninh province, northeastern Vietnam.

The latter shares a border with Guangxi province, China, and the fish were found in a coastal stream draining into the world famous Ha Long Bay.

In 2007 an additional population was discovered on Hainan Island, Hainan province, which is separated from Guangdong by the 30 km wide Qiongzhou Strait (Chan and Chen, 2009).

Questions regarding the genetic status of the Shanwei, Hainan, and Vietnamese populations have been raised as they appear to have been segregated for a considerable period of time meaning phylogenetic studies could yield interesting results.

It’s considered an endangered species by governmental agencies in China and features in the China Red Data Book of Endangered Animals, in which it is listed as a ‘second class state protected’ animal, but has not been evaluated by the IUCN at time of writing.

Reintroduction programmes using captive-bred fish have been implemented but we’ve been unable to obtain details as to their success or failure.

This precarious conservation status is unlikely to affect the aquarium hobby because all the fish on sale are bred on a commercial basis.

Habitat

Little published information exists but one of the populations rediscovered close to the type locality in Guangdong inhabits a sluggish, spring-fed mountain stream with clear, shallow water and dense growths of aquatic vegetation (Yi et al. 2004).

Macropodus opercularis and introduced Gambusia affinis were the only other fish species recorded.

The Hainan Island fish occupy a clear, slow-moving coastal stream and its tributaries with substrates of sand, pebbles and leaf litter and maximum water depth of only 23.6″/60cm even during the wet season.

They were observed swimming in schools in calmer zones and backwaters close to patches of dense, trailing marginal vegetation.

PH was 6.4 with low hardness values and plant species included Blyxa japonica, Rotala rotundifolia, Ludwigia prostrata, Ceratopteris thalictroides and Limnophila sp.

Sympatric fishes were Puntius semifasciolatus, Misgurnus anguillicaudatus, Macropodus opercularis, and Channa gachua as well as non-native Gambusia and Oreochromis.

Maximum Standard Length

30 – 40 mm.

Aquarium SizeTop ↑

Minimum base dimensions of 60 ∗ 30 cm or equivalent are required.

Maintenance

Choice of décor is not especially critical though it tends to show better colouration in a heavily-planted set-up with a dark substrate.

The addition of some floating plants, driftwood roots or branches, and leaf litter also seems to be appreciated and adds a more natural feel.

Filtration does not need to be particularly strong though it does seem to appreciate a degree of water movement and will also do well in a hill stream-type set-up.

Water Conditions

Temperature: This species is subject to seasonal temperature fluctuations in nature and is most comfortable between 14 – 22 °C.

Permanent exposure to warmer conditions is likely to result in a shortened lifespan and in many countries or well-insulated homes it’s best-maintained without artificial heating year-round.

In tests the wild fish from Hainan Island showed a reduced tolerance to cooler temperatures compared with tank-bred specimens, presumably due to their more southerly, i.e., tropical, distribution.

pH: 6.0 – 8.5

Hardness: 90 – 357 ppm

Diet

Stomach analyses of wild specimens have revealed it to be a micropredator feeding on small insects, worms, crustaceans and other zooplankton.

In the aquarium it’s easily-fed but the best condition and colours offer regular meals of small live and frozen foods such as bloodworm, Daphnia, and Artemia alongside good quality dried flakes and granules, at least some of which should include additional plant or algal content.

Behaviour and CompatibilityTop ↑

Very peaceful indeed and an ideal resident of a well-maintained community  set-up provided its temperature requirements are considered.

Other species that enjoy comparable conditions include Pethia conchonius, P. padamya, ‘Puntius‘ semifasciolatus, and Macropodus opercularis (it occurs sympatrically with the latter two in nature) but it doesn’t make a suitable companion for goldfish despite often being sold as such.

In a stream-style tank it can also be combined with rheophilic species from genera such as Danio, Devario, and Garra as well as many loaches.

It’s a schooling fish by nature and ideally a group comprising 10+ specimens should be purchased.

Maintaining such numbers will not only make individuals less nervous but result in a more effective, natural-looking display, and males will display their best colours as they compete with one other for female attention.

Sexual Dimorphism

Mature females are usually rounder-bellied and often a little larger than the slimmer, more colourful males.

Reproduction

Like many small cyprinids this species is an egg-scattering, continuous spawner that exhibits no parental care.

That is to say when the fish are in good condition they will spawn often and when a group is maintained alone in a densely-planted, mature aquarium or outdoor container small numbers of fry usually start to appear without further intervention.

Should a more controlled approach be required a separate, smaller aquarium can be set up.

This should be dimly-lit and the base covered with some kind of mesh of a large enough grade so that the eggs can fall through but small enough so that the adults cannot reach them.

The widely available plastic ‘grass’-type matting can also be used and works well, as does a layer of glass marbles.

Alternatively filling much of the tank with a fine-leaved plant such as Taxiphyllum spp. or spawning mops can also return decent results.

The water itself should be of slightly acidic to neutral pH with a temperature towards the upper end of the range suggested above, and an air-powered sponge filter or air stone(s) included to provide oxygenation and water movement.

When the adults are well-conditioned and the females appear gravid one or two pairs should then be introduced, and spawning should take place the following morning.

An alternative is to spawn the fish in a group with half a dozen specimens of each sex being a good number, although a larger aquarium may be necessary.

In either situation the adults will probably eat the eggs given the chance and should be removed after 2-3 days maximum.

The eggs should hatch in 48-60 hours and once free-swimming the fry may require an infusoria-grade food until large enough to accept microworm, Artemia nauplii, and suchlike.

NotesTop ↑

One of the most ubiquitous species in the aquarium hobby and several ornamental strains are available including ‘long-finned’, ‘golden’, ‘albino‘, and ‘super red’, for which care is identical.

Unfortunately inbreeding among farm-bred stock has resulted in a situation whereby many of the fish available today are genetically weak and prone to disease or develop physical deformities.

We’ve also seen some of the more colourful forms mislabelled as Aphyocypris pooni, a name currently considered a junior synonym of T. albonubes, or A. lini, chosen as a replacement for A. pooni by Weitzman & Chan (1966) and referring to an unrelated species.

T. albonubes was  discovered by a Chinese scoutmaster named Tan Kam Fei in 1932 who passed some specimens on to a local fisheries station, and the director of the station chose to honour the collector by naming the newly-erected genus in his honour.

The genus remained monotypic until 2001 when the Vietnamese species T. micagemmae and T. thacbaensis were described.

The former has been available in the aquarium trade for a number of years but T. thacbaensis is somewhat enigmatic since its description is written entirely in Vietnamese and accompanied only by a line drawing, with photos of live specimens unavailable to date.

A fourth species, currently known only as T. sp. ‘Vietnam’ appeared in the aquarium trade during 2010 and has been available in limited numbers.

T. albonubes is noticeably larger than T. micagemmae and T. sp. ‘Vietnam’, and exhibits an overall reddish-brown colouration in the body that is lacking in the other two and possesses a less broad dark, lateral stripe on the body, below the paler stripe.

In T. micagemmae the ventral and anal fins are reddish, whereas they are bright yellow in T. sp. ‘Vietnam’.

Diagnostic characters for the genus include presence of cornified tubercules on the snout posterior to the premaxila in males, and confluent narial openings.

Less clear is the phylogenetic position of Tanichthys within the family Cyprinidae.

It has been considered closely related to the genera Danio or Rasbora but recent studies, notably that of Fang et al. (2009) have suggested it to be more analagous withTinca tinca, the common tench, and the putative subfamily Acheilognathinae, better known as the bitterlings.

The results also suggested that T. micagemmae is the parent species of the group in evolutionary terms with T. albonubes its younger relative.

References

1. Chan, B.P.L., and X-L Chen, 2009 - Zoological Research 30(2): 209–214
   Discovery of Tanichthys albonubes Lin 1932 (Cyprinidae) on Hainan Island, and notes on its ecology.
2. Fang, F., M. Norén, T. Y. Liao, M. Källersjö, and S. O. Kullander, 2009 - Zoologica Scripta 38(1): 1-20
   Molecular phylogenetic interrelationships of the south Asian cyprinid genera Danio, Devario and Microrasbora (Teleostei, Cyprinidae, Danioninae).
3. Liang, X-F, G-Z. Chen, X-L. Chen, and P-Q. Yue, 2007 - Environmental Bi0logy of Fishes 82(2): 177-178
   Threatened fishes of the world: Tanichthys albonubes Lin 1932 (Cyprinidae).
4. Rüber, L, M. Kottelat, H. H. Tan, P. K. L. Ng, and R. Britz, 2007 - BMC Evolutionary Biology London 7: 1-10
   Evolution of minituarization and the phylogenetic position of Paedocypris, comprising the world's smallest vertebrate.
5. Yi, Z-S., X-L. Chen, J-X. Wu, S-C. Yu, and C-E. Huang, 2004 - Zoological Research 25(6): 551-555
   Rediscovering the wild population of white cloud mountain minnows (Tanichthys albonubes Lin) on Guangdong Province.