Genus Tanichthys. White Clouds, Meteor Minnows, and Sparkling Gems.

Few ornamental fishes have made a successful aquarium debut so soon after their scientific description as Tanichthys albonubes. The type series of this colorful little minnow was collected in 1932 from streams draining Bai Yun Shan—White Cloud Mountain—in China’s Guangdong Province by Tan Kam Fei, a scoutmaster with a keen interest in the flora and fauna of his native region. In appreciation of his efforts, the Chinese ichthyologist S.Y. Lin later in the same year erected the genus Tanichthys for this diminutive and morphologically distinctive cyprinid, whose species name, albonubes (= white cloud), refers to the type locality. The White Cloud Mountain fish was enthusiastically welcomed by the members of Cathay Aquarists, a local aquarium society based in the city of Guangzhou—more familiarly known to Westerners as Canton—as well as by their counterparts in the Hong Kong Aquarium Society.

The first White Clouds, to give T. albonubes the common name by which it is known today, were brought to North America in 1935 by a young hobbyist, C.W. Brownell, who passed them on to O.R. Eastman, a Montreal-based aquarist. Eastman’s efforts to breed the fish enjoyed only a modest degree of success. Although his four wild-caught fish spawned repeatedly, he was able to rear just two males and a single female to maturity. Realizing his own limitations, in 1936 he passed the surviving pair of White Clouds on to William T. Innes of Philadelphia in the hope that the efforts of this noted American aquarist would prove more productive.

Innes was able to both repay Eastman’s generosity by sending him a new batch of fish and place brood-stock into the hands of several commercial fish breeders. Tanichthys albonubes was formally introduced to American hobbyists (Eastman, 1938; Innes, 1938) in the pages of the September 1938 issue of Innes’s magazine, The Aquarium, which also carried advertisements for “the Chinese wonder fish” by dealers based in Philadelphia, St. Louis,and San Francisco. At an asking price of $2.00 each, roughly a day’s wage for a Depression-era factory worker, one wonders how many of these fish found buyers!

The first shipment of White Clouds to Europe was made from Hong Kong in 1937 (Sugars, 1938). Only a dozen of the 2,000 fish in the shipment were still alive when the P & O steamer carrying them docked in England. Although the fish were transported in aerated tanks, most fell victim to the extreme temperatures the ship encountered as it passed through equatorial waters.

Presumably these heavy losses dictated the fishes’ asking price of 50 shillings each. As this sum was close to a week’s wages for a skilled worker in the United Kingdom at the time, one also wonders how quickly the British importer found purchasers for his fish. It is a testimony to both the fecundity of T. albonubes and the ease with which it can be bred that within a decade of its initial importation to both North America and Europe, the “Chinese wonder fish” was being promoted as “the poor man’s Neon Tetra”!

The color plate that graced the cover of the September 1938 issue of The Aquarium depicts a group of White Clouds descended from the wild-caught founders Brownell brought back from China. Their dorsal fins, like those of the population originally described by Lin, have red bases, while their clear yellow anal fins are edged in iridescent white. In his account of the Hong Kong population of T. albonubes, Sugars (1938) describes a fish in which both the dorsal and anal fins sport a red marginal zone.

Hong Kong White Clouds were subsequently exported to San Francisco, where the American ichthyologist Albert Herre encountered them. The color pattern differences between the topotypical and Hong Kong populations led him to suspect that these two color forms might actually be different species. Herre’s suspicions were apparently confirmed when, in 1939, Lin sent him a manuscript that included the description of a new small cyprinid from Hong Kong. Herre (1939), under the twin assumptions that the manuscript had already been published (it hadn’t) and that Lin was proposing a new name for the Hong Kong White Cloud, Aphyocypris pooni (he wasn’t), utilized this name for the Hong Kong fish in a popular article that appeared in advance of Lin’s paper. Herre’s description of A. pooni was sufficiently detailed to satisfy the publication criteria for a species description set forth in the International Code of Zoological Nomenclature, thus assuring this name’s taxonomic validity.

Were they both talking about the same fish, Herre would have done nothing more than inadvertently “scoop” Lin. However, the animal Lin described as A. pooni was a very different fish from the Hong Kong population of T. albonubes. This state of affairs would have been of little concern save to the relatively small number of ichthyologists working with Chinese fishes, but for two unrelated developments. First of all, aquarists discovered that the “classical” T. albonubes illustrated by Innes and the Hong Kong fish, Aphyocypris pooni sensu Herre, interbred freely, producing viable and fully fertile offspring of both phenotypes. This led Innes (1945) to conclude, quitecorrectly, that the two phenotypes in question simply represented geographical races of the same species. What complicated the picture and led to almost two decades of confusion was the entry of the fish described by Lin as Aphyocypris pooni into the aquarium trade. The Garnet Minnow—this fish’s generally accepted common name—looks nothing at all like the Hong Kong White Cloud.

In consequence, publications purporting to distinguish between T. albonubes and A. pooni, as exemplified by the account in Sterba (1962), have something of the flavor of the Indian parable about six blind men describing an elephant.

Resolution of this situation came with the publication in 1966 of a definitive paper by S.M. Weitzman and L.L. Chan. After examining relevant type material, they concluded that, as the two descriptions clearly do not refer to the same animal, Lin’s name is a junior homonym of Herre’s. Furthermore, they determined that Herre’s A. pooni was morphologically indistinguishable from T. albonubes and thus a junior synonym of that species, while Aphyocypris pooni Lin 1939 was referable to the genus Hemigrammocypris and thus did not merit separate generic status. Under the provisions of the Code, the name pooni was no longer available for Lin’s species, so they proposed Hemigrammocypris lini as a replacement name for the Garnet Minnow. Although Weitzman and Chan’s paper should have put to rest any doubts about the taxonomic status of the Hong Kong population of the White Cloud, the use of the cheironyms Tanichthys linni or Tanichthys albonubes var. linni for these fish on wholesalers’ price lists, as well as on some web sites, suggests that is not the case.

Weitzman and Chan also took a stab at determining to which of the several recognized cyprinid subfamilies the White Cloud belonged. In this endeavor they were less successful. Upon careful examination, they were able to identify two unique anatomical features that unambiguously defined the genus Tanichthys and set it apart from all other representatives of the enormous family Cyprinidae known to them. In the White Cloud, the two nostrils on either side of the head are not separated by a fleshy ridge but instead share a common pit-like opening, and a row of small, horny tubercles is present along the side of the upper jaw.

Lin had tentatively suggested that the danios were most closely related to Tanichthys, a notion that is still shared by many tropical fish wholesalers, who lump the two together on their price lists. Weitzman and Chan were unable to find any of the anatomical features that defined the danio lineage in the White Cloud. Nor did they find any evidence that Tanichthys belonged in the subfamily Leuciscinae, a large assemblage of Eurasian and North American minnows. In point of fact, the nostrils of representatives of the diminutive West African genus Barboides also open into a common pit, but these fishes,representatives of the subfamily Barbinae, are in all other respects quite dissimilar. The sister-group relationships of Tanichthys remain obscure, although more recent molecular analyses (Fang et al., 2010) suggest that the White Cloud’s closest relatives are the morphologically very different bitterlings (subfamily Acheilognathinae) and Tinca tinca, the Eurasian Tench (subfamily Tincinae).

Since its original description, it has been assumed by ichthyologists and aquarium hobbyists alike that the genus Tanichthys was monotypic, comprising only a single species. The fallacy of this assumption was demonstrated by the description in 2001 of two new Tanichthys species. Tanichthys micagemmae Freyhof and Herder 2001 was described from specimens collected from Bu Dong Creek, a small stream tributary to the Ben Hai River just north of the city of Dong Ha in central Vietnam. My initial reaction to the excellent color photograph accompanying the description was that T. micagemmae had a real future as an aquarium fish. Apparently quite a few other people—some of them in a position to do something about it—also felt that this species would be of interest to hobbyists. In a manner strikingly reminiscent of the history of T. albonubes, T. micagemmae was available from exporters in Singapore the same year it was described and made its North American aquarium debut almost immediately thereafter. This species has been marketed under the somewhat misleading name “Vietnamese White Cloud.” As its locality of origin lies many miles to the south of White Cloud Mountain, I suggest that Sparkling Gem Minnow, a literal translation of its specific name, is a more appropriate name for this beautiful little fish.

The same year also saw the description of a third Tanichthys species, Tanichthys thacbaensis Nguyen and Ngo 2001. As the specific name thacbaensis implies, the type series was collected from the basin of Thac Ba Lake, a reservoir formed by the damming of the Chay River in Vietnam’s Yen Bai province. Impressed by his customers’ positive response to the Sparkling Gem Minnow, my friend Frank Greco, who has a small fish import business (www.franksaquarium. com), asked me in 2010 what I could tell him about “the other Vietnamese White Cloud.” I had to confess ignorance, as the species description-written in Viet-namese—was published in a hard-to-find multi-volume treatment of the freshwater fishes of Vietnam. All I could tell him was that the type locality was a long way from Vietnam’s main focus of ornamental fish exportation in Saigon and relatively difficult of access. I thus felt fairly confident in predicting that aquarists would not be seeing T. thacbaensis any time soon.

Frank had also concurrently expressed an interest in this species to Patrick Yap, one of his suppliers. Patrick, a Singapore-based exporter, replied that as ornamental fishes were now being regularly exported from Vietnam, he felt it was only a matter of time before T. thacbaensis made its debut as an aquarium fish. He was right: this species made its appearance in the United States under the name Lemon White Cloud in 2011. I have since given up on predicting when—or even whether—aquarists are likely to see a newly described fish species!

Mutation happens

William T. Innes (1938) predicted that the White Cloud was destined to enjoy enormous popularity and would eventually become the Guppy of egglayers. Colorful, hardy, easily bred, and prolific, T. albonubes has indeed lived up to Innes’s expectations. White Clouds are effectively ubiquitous in retail establishments worldwide.

As is often the case when an ornamental fish is produced in huge numbers, mutant individuals have appeared that have allowed breeders to selectively breed distinctive White Cloud variants.The first of these, a long-finned variant initially marketed as the Meteor Minnow, made its debut in the 1960s. Unlike the long-finned variants of the Rosy Barb and Serpae Tetra, in which indeterminate fin growth destroys an individual’s basic symmetry and can actually impede its swimming ability, fin growth in the Meteor Minnow is determinate. The fish’s basic symmetry is thus preserved. I am not a fan of most long-finned fish varieties, but the Meteor Minnow is always a welcome guest in my fish room. A golden form of the White Cloud with normally pigmented eyes, but otherwise devoid of black pigment, is also widely available. I have not been able to pinpoint the date of its introduction, but the Golden White Cloud began to make regular appearances on wholesalers’ price lists in 2002. The most recent of these catatechnic color forms is the so-called Super Red White Cloud, in which the red coloration present in the caudal fin extends into the posterior third of the flanks.

Water preferences

All three Tanichthys are ideal aquarium residents. They are undemanding with regard to water chemistry, prospering over a pH range of 6.0-8.0 and hardness values up to 14°dH. Like most stream fishes, they do not appreciate dissolved waste buildup and do best under a regime of regular partial water changes. The three species do differ with regard to their preferred water temperature. Native to southern China and the extreme north of Vietnam (Kottelat, 2001), the White Cloud is not a true tropical fish. In nature, it experiences a temperature range of 41-77°F (5-25°C). In captivity, it can tolerate brief exposures to water temperatures at the upper end of its range.

However, prolonged exposure to temperatures above 81 °F (27°C) are usually fatal—recall the fate of the first shipment of White Clouds sent from Hong Kong to England. Individuals kept in tanks where temperatures never fall below 75°F (24°C) are much more susceptible to velvet disease and rarely live more than a year. Fish kept in unheated tanks are much less prone to parasitic diseases and can live for up to three years, a very respectable span for a fish that rarely attains 1 inch (c. 25.0 mm) in total length.

On the other hand, the type locality of both the Sparkling Gem and the Topaz Minnow, which I suggest as a common name for T. thacbaensis, do lie squarely in the tropics. While both T. micagemmae and T. thacbaensis can handle temperatures as low as 59°F (15°C) without difficulty, tank temperatures between 75 and 81°F (24-27°C) appear to affect neither their ability to resist disease nor their longevity.

As might be expected in view of their temperature preferences, Tanichthys species make very satisfactory summer pond residents in most of North America. I have no experience in this regard, but several members of my local aquarium club, the North Jersey Aquarium Society, make a practice of giving their fishes a summer vacation outdoors. They have found that in U.S. Department of Agriculture Zone 6, it is best to wait until the beginning of June before moving Tanichthys outside. Water temperatures tend to fluctuate rather abruptly earlier in the year, and this can prove stressful for fish that have spent the winter in a relatively stable thermal environment.That said, one need not be too hasty about bringing White Clouds back inside for the winter. North Jersey member Ted Colletti, a noted livebearer breeder who is also an active water gardener, routinely waits until early November before retrieving White Clouds from his ponds. The fish apparently can cope quite well with slow temperature drops. Given their provenance, it would probably be prudent to bring T. micagemmae and T. thacbaensis back indoors no later than the end of September. Due to their essentially subtropical character, I strongly suspect that White Clouds could be expected to overwinter successfully in USDA Zones 7 and 8; elevated summer temperatures would likely be the limiting factor in the ability of the Sparkling Gem and Topaz Minnow to thrive in these zones. (In small water gardens receiving direct sunlight, shading from overhanging and floating plants may be needed to keep water temperatures within safe limits.)

Feeding and keeping

These are easily fed little fish. They will eagerly consume any foods—live, frozen, or prepared—small enough to fit in their mouths. Daphnia, Artemia nauplii, and Grindal worms represent ideal live food choices, but these fish also relish frozen CYCLOP-EEZE and Ocean Nutrition’s Prepared Baby Brine Shrimp. I have found that frozen bloodworms and glassworms are also appreciated, although it is necessary to chop these rather large food items into smaller pieces before feeding them. These are intensely social little fish and will not prosper unless maintained in a group of at least six individuals. Like most small fishes, Tanichthys feel most at home and look their best in a planted tank. While they certainly make a lovely addition to a Leiden- or Amano-style planted aquarium, all three species are equally comfortable if their tank’s aquascaping consists of no more than a generous clump of Java Moss and a layer of floating plants.

By preference, Tanichthys occupy the upper half of their aquarium’s water column. Both this fact and their small adult size must be given consideration when selecting their tankmates. It should be self-evident that these fish should only be kept with companions of the same general size. However, it is equally important to avoid extremely active companions who also prefer to swim in the upper reaches of an aquarium. Danios—even relatively small species such as Danio choprae or D. nigrofasciatus—do not make good tankmates for species in the White Cloud group. They will out-compete the Tanichthys at feeding time and tend to inhibit the normal social interactions that make the White Cloud and its relatives such appealing aquarium residents.

Companions more than half again their total length, even if they habitually frequent the lower half of the water column, also tend to inhibit the expression of the full range of the White Clouds’ social behavior and push them toward the uppermost reaches of the water column. Small rasboras of the genera Boraras and Trigonostigma make excellent tankmates for Tanichthys, as do Microdevario species. I have found that the smaller Asian barbs, such as Puntius gelius, P. phutunio, and P. titteya, also make suitable companions. The same is true of dwarf loaches of the genera Yunnanilus and Yasuhikotakia. While I have never tried the combination, I suspect that dwarf African barbs, such as Barboides gracilis, “Barbus” jae, “B.”candens, and “B.” hulstaerti, could also be expected to coexist amicably with Tanichthys.

In my experience, tetras do not constitute appropriate tankmates for Tanichthys. I found that when housed with White Clouds, even miniature species such as the Ember Tetra, Hyphessobrycon amandae, and the Flame Tetra, H. flammeus, are a bit too inclined to nip their companions’ fins. Tanichthys do not seem inhibited by the presence of small labyrinth fishes, such as the Honey Gourami, Colisa chuna, or the Sparkling Gourami, Trichopsis pumilis. As it also prefers cool water, the Burmese Chocolate Gourami, Parasphaerichthys ocellatus, is an appropriate tankmate for T. albonubes. I was also pleasantly surprised by the indifference of a group of T. thacbaensis to a pair of Microgeophagus ramirezi. On the strength of that experience, I am experimenting with a group of Meteor Minnows as dither fish for the diminutive Apistogrammoides pucallpaensis. Since the jury is still out on how well this arrangement will work in the long run, I would still be very hesitant about using any Tanichthys species as dither for dwarf cichlids with a more robust build and larger mouths!

Spawning and rearing

There is a great deal to be said for housing Tanichthys in a single-species tank. They are certainly sufficiently active and sport bright enough colors to successfully carry off such a starring role. A group of six to eight individuals makes for an eye-catching display in a 3- to 5-gallon (11-19 L) mini-cube aquarium. When not inhibited by the presence of other fish species, male Tanichthys interact constantly, and their highly ritualized displays are a delight to behold. Such activity is most intense early in the day, which— not coincidentally—is also when spawning activity is at its peak. Tanichthys, like many other diminutive fish species, are continuous spawners, and females ripen a small number of eggs every few days. With the coming of first light, males actively vie for the attention of receptive females. Unlike many other cyprinids, adult Tanichthys are not avid egg-eaters, and when well fed will ignore their own free-swimming fry. A planted aquarium affords adults plenty of spawning sites as well as an environment that encourages the development of a community of microscopic organisms on which newly hatched fry can forage until they grow large enough to take Artemia nauplii and finely powdered prepared foods. Assuming that both sexes are present, the appearance of fry is inevitable when Tanichthys are housed in this manner. Innes was right on the mark when he predicted that the White Cloud was destined to become “the Guppy of egglayers.”

It must be noted that this casual approach to breeding Tanichthys has its limitations. While adultsare not given to snacking on their progeny, the same is not true of juveniles. In my experience, recruitment continues until the first fry reach a length of .5 inch (1.2 mm) total length, at which point the populations of smaller fry abruptly disappear. Newly mobile fry do not begin to reappear until the first batch of fry begin breeding themselves, at just under an inch (c. 2.0 cm) total length.

The size of the initial cohort produced by a breeding group is also strongly influenced by their tank’s furnishings. A 5-gallon (19-L) tank containing a large clump of Java Moss, a layer of floating plants, and, most important, an active sponge filter will provide plenty of foraging opportunities for newly mobile fry and thus maximize survivorship. Once the first fry have been observed, the adults should be shifted to a new breeding setup if the aim is to maximize fry production. At this point, regular offerings of appropriately sized live and prepared foods will assure rapid growth. Paradoxically, the metallic green mid-lateral stripe that earned T. albonubes the designation of “poor man’s Neon Tetra,” and also features prominently in the color pattern of T. micagemmae, is most intense in fish between 0.5 and 0.75 inch (1.0-2.0 mm) total length. A tankful of Tanichthys fry in this size range is truly a sight to behold.

At the brink of extinction

Given its status as a staple of the aquarium hobby, it will probably come as a surprise to readers of this article that T. albonubes is classified as critically endangered (Yue and Chen, 1998). As alarming as this seems, it represents a dramatic improvement in the White Cloud’s conservation status—in the 1980s it was believed to be extinct in nature (Liang et al., 2008). In addition to the Vietnamese population already alluded to, relict populations have been recently discovered in Guangdong province on the Chinese mainland (Yi et al., 2004) and on the island of Hainan (Chan and Chen, 2009). Habitat degradation caused by deforestation and the erosion that invariably follows the loss of forest cover from steep slopes appears to be the primary reason for the disappearance of this diminutive minnow from most of its formerly extensive range. Detailed information on the conservation status of T. micagemmae and T. thacbaensis is lacking, but given the apparently very limited known ranges of both species, they would be classified as endangered following the criteria established by the International Union for the Conservation of Nature.

As all of the known wild Tanichthys populations lie outside of protected areas in landscapes that continue to be profoundly modified by human activity, it is difficult to be optimistic about their near-term survival prospects. While their extirpation would be tragic, the existence of a captive population of T. albonubes whose size certainly exceeds by several orders of magnitude that of this species’ total free-living population guarantees that extinction in the wild will not be synonymous with global extinction for the White Cloud.

Indeed, the White Cloud’s circumstances illustrate dramatically the role that the ornamental fish hobby can play in assuring the survival of T. micagemmae, T. thacbaensis, and the many other small tropical freshwater species that rarely attract the attention of either governmental or non-governmental conservation agencies. The large-scale commercial production of such species constitutes, in effect, a self-financing captive breeding program that assures the survival of species at risk until such time as their circumstances in the wild improve, or, in the most extreme case, allow their reintroduction. I therefore strongly urge readers to make every effort to welcomethe Sparkling Gem and Topaz Minnows to the ranks of ornamental fishes with the same enthusiasm that their forebears in the hobby embraced the White Cloud.

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