#cyprinids

One of the species traded, was R. ocellatus, the rosy species from East Asia. In fact the species once had a much smaller range, for it was once restricted entirely to the island of Taiwan. Centuries ago, this species was introduced to mainland China, as well as Korea and Japan. Since those days, populations have invasively colonised quite far flung locations, but the latitudinal range of this species in Asia, ought to inform us as to its tolerances. For it is established in Beijing just as it is in Hong Kong, although the latitude of Beijing suffers far more severe winters.

Rosy bitterlings are common in vegetated farm ponds and irrigation channels, and they grow to around 9 centimeters, or under 4 inches long. These species display sexual dimorphism, with the females growing to only a mere 2/3 of the length of their male counterparts. Originally this species preferred lakes, natural ponds, and sufficiently slow moving rivers. But now it is quite synanthropic, and is considered a nuisance on fish farms, where they are believed to compete with the juveniles of the cultivated species.

Rosy bitterlings appreciate a rather neutral pH, and a temperture range suited for a warm temperate to subtropical fish. 28 degrees centigrade might be regarded as a good upper limit duriǹg the summer season, dropping to a few degrees below zero, in the wintertime. Although this fish has become established long ago, in some regions where the winter air temperature is often below freezing, most of its populations do not. And it is unnecessary to expose this fish, to such low winter temperatures. Although a winter drop in temperature, is natural for these bitterlings.

The White Cloud Mountain minnow (Tanichthys albonubes) is not as popular in aquaria as once it was, because of the efficiency and availability of aquarium heating. Formerly the species was popular, because of its resilience to cold tempertures, being a subtropical rather than a tropical fish. Historically they were even described as the poor man's neon tetra, a reference to an unrelated fish of similar schooling habits, but since those days, the actual neon tetra is more widely traded.

This doesn't mean that T. albunodes isn't appealing, nor widely unavailable, traded in a number of selectively bred, domesticated morphs, bred from the standard wild forms. Variability in the coloration of wild T. albunodes, which predisposed the wild stock to be domesticated into color morphs, was formerly a minor source of taxonomic confusion for ichthyologists. Also the traditional T. albonubes, includes populations that are now regarded as distinct species, belonging to the same cyprinid genus, Tanichthys.

These wild ancestral fish, are native to clear, sluggish brooks with thick, submerged vegetation, from Guangdong Province in the south of China, south to nearby Quang Ninh Province in northern Vietnam. T. albonubes require the lush plants in their habitat, as a substrate on which to spawn. Wild populations have a disjunct distribution, and because of localised processes of natural selection, the different populations are proved not to have identical ambient requirements.

The species was, however, initially described from the Baiyun (or White Cloud) mountain range of mainland China, where the water temperture varies, according to the season, from 10 to 30 degrees. There the water pH of the upland streams, is noted to be 5.6 to 6.5. Although wild T. albonubes do not live in deep lakes, they have been found able to persist, where water surface tempertures are below freezing, by retreating to deep water. This should not be used as an excuse, to subject these cyprinids to tempertures below 5 degrees centigrade, as their origins are subtropical, and they are expected to suffer moralities, at lower tempertures.

Although T. albonubes has declined in the wild, its global popularity in the aquarium trade, has led to this adaptable species, having now established feral populations in countries such as Colombia, Madagascar, the USA, and Australia, where humans have introduced it into suitable habitats. For this important reason, it is considered a potentially invasive species, and a risk to established ecosystems, in places such as New Zealand, where conditions are appropriate for newly wild populations.

The maximum length reported for T. albonubes, is 4 centimeters or over 1 and a 1/2 inches, although half of this length, is more common. Like many small cyprinids, this is a schooling species, and the aquarist should only maintain them as such, is a planted aquarium. Wild T. albonubes are micropredators, feeding on zooplankton and meiobenthos. Captive fish are unfussy about their food, taking tiny defrosted 'prey', and suitably composed dried preparations.

Owing to their geographical origin, wild T. albonubes evolved wide temperture tolerances, in a seasonal climate. T. albonubes can survive water temperatures below 15 degrees centigrade, and fish from northern populations, can survive winter tempertures as low as 5 degrees. Conversely in the summertime, T. albonubes may experience much warmer tempertures, as high as 29 or 30 degrees.

Although a temperture preference of 18-22 degrees is often cited for T. albonubes in books, and online, and these fish are fine year round at such tempertures, it does not replicate the seasonality these animals know in their streams of origin. Fishes from the south of their wild range, also have less tolerance of cool tempertures, than do those from further north, actually suffering mortalities below 15 degrees.

Pethia nigrofasciata is a Ceylonese carp, traded as the black ruby barb, but also known as the purplehead barb. Historically the species was regarded as belonging to Barbus or Puntius. It grows to about 6.5 centimeters, or about 2 and a 1/2 inches in length. It is native to winding, elevated forest streams, above flood level, from the Kelani to Nilwala basins in the southwest of the island. The waters in such streams are on the soft, acidic side, and are clear, cool, and shaded.

The fish mainly preys on the aquatic larvae of chironomid flies, and ephemerooteran nymphs, as well as green algae and diatoms, and for that reason belongs to the ecological guild of fish that feed near the stream bottom. The mouth of this species is subterminal, befitting such a benthic feeder, and its gill rakers are widely spaced. Other cyprinid species sharing its habitat, consume prey in midwater, or from the water surface. P. nigrofasciata is also distinct by its preference for shallow water, and the fringes of branch and root systems.

P. nigrofasciata in fact has specific habitat requirements, living where the bottom is sandy with some rocks or submerged wood, and maybe a few clumps of macrophytes, typically Aponogeton. Though the forest shades the streams, P. nigrofasciata prefers the full sun, being recorded in waters with a temperture of 25 or 26 degrees centigrade. Such habitats also have a pH of about 6.

As far as I know, these are the only (foreign) captive specimens of Puntius Tumba I’ve found. Possibly the last survivors of Lake Lanao’s endemic Cyprinid flock.

(Medium grayish-green Barb with reddish fins)

Lake Lanao’s 2 remaining species of endemic cyprinids.

There used to be a total of 18 species.

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- Puntius Lindog