Tanichthys albonubes - White Cloud Mountain Minnow

Cyprinidae

First discovered at White Cloud Mountain (also known as Mount Baiyun or Baiyunshan) a few miles north of the city of Guangzhou, Guangdong Province, China and thought to be restricted to the surrounding Pearl River Delta region. Unfortunately it has probably been extirpated from that locality; the "mountain" is actually a collection of thirty or so peaks and is now a very popular tourist resort complete with cable car access, hotels and public parks. Between 1980 and 2001 the species went unrecorded in nature leading to fears of its extinction.

Since then a handful of relict wild populations have been rediscovered close to the type locality and at isolated spots in coastal Guangdong province (in the prefecture-level city of Shanwei) and Quảng 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 Hạ Long Bay. A further, isolated population was discovered in 2007 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 is 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 have been unable to obtain details as to their success/failure. This precarious conservation status does not affect the aquarium hobby because all the fish seen on sale are produced commercially in the Far East or Eastern Europe.

Scant 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. The substrate is composed of sand, pebbles and leaf litter and even during the wet season the maximum water depth was only 23.6"/60cm. They were observed swimming in schools in calmer zones and backwaters close to patches of dense, trailing marginal vegetation. The pH was 6.4 with low hardness values and plant species present included Blyxa japonica, Rotala rotundifolia, Ludwigia prostrata, Ceratopteris thalictroides and Limnophila sp. Other fish included Puntius semifasciolatus , Misgurnus anguillicaudatus , Macropodus opercularis  and Channa gachua  as well as non-native Gambusia and Oreochromis.

Around 1.6"/4cm.

A tank measuring 24" x 15" x 12"/60cm x 37.5cm x 30cm/70.8 litres is big enough to house a small group of these active fish.

Fairly undemanding provided its tank is well-maintained. It does tend to appear a little pale in very sparsely decorated set-ups though, and a combination of subdued lighting and a dark substrate will encourage it to show its best colours. It can look quite superb in a heavily-planted arrangement decorated with pieces of bogwood, twisted roots and patches of floating vegetation, for example.

It will also do well in a set-up designed to resemble a flowing stream with a substrate of variably-sized rocks and gravel, some larger, water-worn boulders and perhaps a couple of driftwood branches. A rivertank manifold could even be constructed to provide naturalistic unidirectional flow, although given the available habitat information torrent-like conditions should be avoided. While the majority of aquatic plants will fail to thrive in such conditions possibilities include hardy species such as Java fern, Bolbitis or Anubias which can be grown attached to the decor.

This subtropical (NOT coldwater) species is subject to seasonal temperature fluctuations in nature and is most comfortable between 60 - 72°F/16 - 22°C. Permanent exposure to warm conditions is likely to result in a shortened lifespan and in many countries/well-insulated homes it is 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.

Today's farm-bred fish are adaptable and comfortable within the range 6.0 - 8.0.

5 - 20°H

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 will accept dried foods of a suitable size but should not be fed these exclusively. Daily meals of small live and frozen fare such as Daphnia, Artemia and suchlike will result in the best colouration and encourage the fish to come into breeding condition.

This species is very peaceful indeed making it an ideal resident of the well-maintained community tank provided its temperature requirements are accounted for. Other species that enjoy comparable conditions include Puntius conchonius , P. padamya , P. semifasciolatus , Macropodus opercularis  (it occurs sympatrically with the latter pair in nature) and some Badis. In a stream-style tank as described above it can also be combined with rheophilic species from genera such as Danio, Devario and Garra as well as many Balitorine and Nemacheilid loaches. It does not really make a suitable companion for goldfish despite often being sold as such.

This is a schooling fish by nature and should always be kept in a group of at least 8-10 specimens. Maintaining decent numbers will not only make individuals less nervous but will result in a more effective, natural-looking display. Males will also display their best colours as they compete with one other for female attention.

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

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 (during warmer months) small numbers of fry usually start to appear without further intervention.

However if you want to increase the yield of fry a slightly more controlled approach is required. The adult group can still be conditioned together but one or more smaller, say 16" x 8" x 8"/40cm x 20cm x 20cm/16 litre tanks should also be set up. Decor can be very simple; a couple of good-sized clumps Anubias, Echinodorus will give the fish somewhere to deposit their eggs and there is no need to add a substrate. The water should be of slightly acidic to neutral pH with a temperature towards the upper end of the range suggested above. A small, mature, air-powered sponge unit bubbling away gently is all that is needed in terms of filtration.

A pair of adults should then be added to each spawning tank; try to select the fattest looking female(s) and best coloured male(s). Spawning may not occur immediately but when it does can continue for up to a day before the female is spent of eggs. The pair(s) can be left in situ for two or three days then removed as the first eggs should hatch within 48-60 hours. Once the tiny fry can be seen swimming freely they will require Paramecium or other microscopic food, and after a week or so should be large enough to accept Artemia nauplii/microworm etc.

Tanichthys albonubes is without doubt one of the most ubiquitous species in the hobby and is now available in several 'sport' varieties including 'long-finned', 'golden', 'albino' and 'super red', although we don't think any beat the colour of the wild form. As the latter are no longer exported for the hobby the best chance of obtaining higher grade fish lies in locating a local breeder who is maintaining a strong strain. The widely available mass-produced ones do not seem to exhibit the same depth of colour seen in good quality, privately-bred specimens and in recent years deformities related to inbreeding have started to become commonplace. We've also seen some of the stronger colour forms mislabelled as Aphyocypris pooni, that name now considered a junior synonym of T. albonubes, or A. lini, chosen as a replacement for pooni by Weitzman & Chan (1966) and currently representing an unrelated species.

The story of how the taxon got its name is well-known, Tanichthys albonubes first being discovered by a Chinese scoutmaster named Tan Kam Fei in 1932 who passed some specimens on to the local fisheries station. The director of the station chose to honour the collector by naming the newly-erected genus in his honour. Until 2001 it remained monotypic but in that year two new species were described from Vietnam; T. micagemmae and T. thacbaensis. The former has now been available in the trade for a number of years and is an excellent aquarium fish though it may well be critically endangered in nature. T. thacbaensis is somewhat more mysterious, having been described by two Vietnamese authors in the first volume of a series of books on native freshwater fish species. This is written entirely in Vietnamese, is now out of print and only a small number of copies were produced. The fish, meanwhile, has never been seen in pictures or the trade as far as we know.

The two species available to hobbyists are very easy to tell apart. Tanichthys albonubes is a noticeably larger fish and exhibits an overall reddish-brown colouration in the body that is lacking in T. micagemmae. It also possesses a much thinner dark lateral body stripe. Less clear is the phylogenetic position of the genus within the order Cypriniformes. It has long been considered to be a danionine/rasborine taxon but recent studies have suggested its closest relatives are actually Tinca tinca (the common tench) and the subfamily Acheilognathinae, better known as the bitterlings. The results also appear to suggest that T. micagemmae is the parent species of the group in evolutionary terms with albonubes its younger relative.

Literature cited

1. Chan, B.P.L., and X-L Chen. 2009 - Zoological Research 30: 209–214.
   Discovery of Tanichthys albonubes Lin 1932 (Cyprinidae) on Hainan Island, and notes on its ecology.
2. Liang, X-F, G-Z. Chen, X-L. Chen and P-Q. Yue. 2007 - Env. Biol. Fishes 82 (2): 177-178.
   Threatened fishes of the world: Tanichthys albonubes Lin 1932 (Cyprinidae).
3. Yi, Z-S., X-L. Chen, J-X. Wu, S-C. Yu and C-E. Huang. 2004 - Zool. Res. 25(6): 551-555.
   Rediscovering the wild population of white cloud mountain minnows (Tanichthys albonubes Lin) on Guangdong Province.
4. Fang, F., M. Norén, T. Y. Liao, M. Källersjö and S. O. Kullander. 2009 - Zoologica Scripta, v. 38 (no. 1): 1-20.
   Molecular phylogenetic interrelationships of the south Asian cyprinid genera Danio, Devario and Microrasbora (Teleostei, Cyprinidae, Danioninae).
5. Rüber, L, M. Kottelat, H. H. Tan, P. K. L. Ng and R. Britz. 2007 - BMC Evolutionary Biology, 7, 38.
   Evolution of minituarization and the phylogenetic position of Paedocypris, comprising the world's smallest vertebrate.