Sinogastromyzon puliensis LIANG, 1974

Etymology

Sinogastromyzon: from the Latin sina, meaning ‘from China’ (used as a prefix in this case), Greek gaster, meaning stomach, and Greek myzo, meaning ‘to suckle’.

Classification

Order: Cypriniformes Family: Balitoridae

Distribution

Endemic to western river drainages of central and southern Taiwan including the Kaoping, Tsengwen, Choshui, Tatu and Tachia systems with type locality ‘Pu-lo, (Tatuchi, Puli), Taiwan’.

Phylogenetic studies have suggested the Kaoping population to be ancestral thus implying the species is southern in origin and migrated progressively northwards.

It’s considered endangered across some of this range due to sandstone extraction, over-exploitation of water resources and dam construction, and has been protected by the Wildlife Conservation Act of Taiwan since 1989.

In particular the Tachia River has undergone near total destruction via construction of riverside embankments.

Habitat

S. puliensis mostly inhabits the middle and upper reaches of rivers and streams and tends to be restricted to stretches of riffles or rapids with swift currents.

It’s most abundant in shallow (20 – 60 cm deep) habitats characterised by substrates of pebbles, variably-sized rocks and a lack of aquatic vegetation.

The most favourable habitats contain clear, oxygen-saturated water which, allied with the sun, facilitates the development of a rich biofilm carpeting submerged surfaces.

During periods of high rainfall some streams may be temporarily turbid due to suspended material dislodged by increased (sometimes torrential) flow rate and water depth.

It performs an annual migration as part of its life cycle, with newly-hatched fry washed downstream and juveniles/young adults moving upstream in large numbers as they mature.

In the middle Choshui River basin migratory fish species are provided with a means of passage past the Jiji Weir via an artificial fish ladder consisting of a single downstream entrance, 72 pools and 9 upstream exits, of which only one is open at any given time.

Due to the action of water exiting the fish ladder the river bed at the entrance has been eroded resulting in the appearance of a metre-high cascade through which migrating S. puliensis are unable to pass.

To combat this the fish literally climb the wall of the entrance, forming a continuously moving row during the annual migratory period, and aggregating in large numbers when the exit of the fish ladder is closed.

Species inhabiting comparable environments in Taiwan include Hemimyzon formosanum, Formosania lacustre, Rhinogobius brunneus, R. candidianus, Acrossocheilus formosanus, and Zacco pachycephalus.

Maximum Standard Length

70 – 80 mm.

Aquarium SizeTop ↑

Minimum base dimensions of 75 ∗ 30 cm or equivalent are recommended.

Maintenance

Most importantly the water must be clean and well-oxygenated so we suggest the use of an over-sized filter as a minimum requirement.

Turnover should ideally be in excess of 15-20 times per hour so additional powerheads or airstones should be employed as necessary. Truly torrential conditions are unnecessary but tolerated.

Base substrate can either be of gravel, sand or a mixture of both to which should be added a layer of water-worn rocks and pebbles of varying sizes and perhaps some driftwood roots and branches.

Although not a feature of the natural habitat aquatic plants can be used with hardier genera such as Microsorum, Crinum and Anubias spp. likely to fare best.

Like many species that naturally inhabit running waters it’s intolerant to the accumulation of organic wastes and requires spotless water at all times in order to thrive.

As stable water conditions are obligatory for its well-being this fish should never be added to biologically-immature aquaria, and be sure to use a tightly-fitting cover as it can climb glass.

Water Conditions

Temperature: For general care 20 – 24 °C is recommended but it can withstand temporarily warmer conditions provided dissolved oxygen levels are maintained.

pH: 6.0 – 8.0

Hardness: 18 – 215 ppm

Diet

Sinogastromyzon spp. are specialised micropredators and biofilm grazers feeding on small crustaceans, insect larvae and other invertebrates with some algae taken as well.

In captivity some sinking dried foods may be accepted but daily meals of live or frozen Daphnia, Artemia, bloodworm, etc., are essential for the maintenance of good health and it’s highly preferable if the tank contains rock and other solid surfaces with growths of algae and other aufwuchs.

If unable to grow sufficient algae in the main tank or you have a community containing numerous herbivorous fishes which consume what’s available quickly it may be necessary to maintain a separate tank in which to grow algae on rocks and switch them with those in the main tank on a cyclical basis.

Such a ‘nursery‘ doesn’t have to be very large, requires only strong lighting and in warmer climates can be kept outdoors.

Balitorids are often seen on sale in an emaciated state which can be difficult to correct.

A good dealer will have done something about this prior to sale but if you decide to take a chance with severely weakened specimens they’ll initially require a constant source of suitable foods in the absence of competitors if they’re to recover.

Behaviour and CompatibilityTop ↑

Very peaceful although its environmental requirements limit the selection of suitable tankmates somewhat, plus it should not be housed with any much larger, more aggressive, territorial or otherwise competitive fishes.

Potential options include small, pelagic cyprinids such as Tanichthys, Danio, and Rasbora, stream-dwelling gobies from the genera Rhinogobius, Sicyopterus, and Stiphodon, plus rheophilic catfishes like Glyptothorax, Akysis and Hara spp.

Some loaches from the families Nemacheilidae, Balitoridae and Gastromyzontidae are also suitable but others are not so be sure to research your choices thoroughly before purchase.

Regarding conspecifics it’s best described as ‘loosely gregarious‘ so buy a group of 4 or more if you want to see its most interesting behaviour.

It’s territorial to an extent with some individuals appearing more protective of their space than others (often a prime feeding spot). This may be related to gender since males in some related species are known to be more aggressive than females.

At any rate physical damage is rare and such battles are very entertaining to watch. Sinogastromyzon spp. tend to be quite reclusive compared to most other balitorids and maintaining them in numbers may also help offset this to a certain extent.

Sexual Dimorphism

Males have a relatively slimmer body shape, and the angle at which the pectoral-fin meets the head is comparatively sharp, whereas the opposite is true in femaes (see images).

These differences are most obvious when the fish is viewed from above or below.

Reproduction

Though nothing has been recorded in aquaria this species is known to be a seasonal spawner in nature.

It lays demersal eggs and Liao et al. (2008) hypothesised that the fry drift downstream post-hatching before migrating upstream as juveniles following full development of the pelvic region which provides the majority of ‘sucking’ capacity.

The authors also suggested that spawning occurs during the annual rainy season between May and September with upstream migration occurring from August to November.

NotesTop ↑

This species is a relatively recent addition to the aquarium hobby but considering the number of specimens allowed to be collected for scientific research is highly restricted by the Taiwanese Council for Agriculture it seems odd that it’s become available at all.

Indeed it appears that those in the trade are collected and exported on an illegal basis (T-Y Liao, pers. comm.).

It may appear superficially similar to some congeners but can be told apart by the following combination of characters: no scales on upper surface of paired fins or the area between underside of pectoral-fin origin and pelvic-fin origin; presence of spots on upper surface of pectoral-fin base; pelvic fins extending beyond anus; regular dark blotches present on dorsal surface of body; caudal peduncle length less than caudal peduncle depth; 60–65 lateral-line scales; 23–25 predorsal scales.

Sinogastromyzon is distinguished from other balitorid genera by a combination of characters as follows: head and anterior portion of body relatively short, depressed and ventrally flattened; paired fins horizontal and laterally expanded, with 2 or more simple rays; pelvic fins fused posteriorly to form a sucking disk; eyes superolateral; mouth inferior and transverse; 4 rostral and 4 maxillary barbels aligned in rows; gill opening relatively large and extending to pectoral-fin.

The genus currently appears restricted to southern mainland China, Taiwan, Laos, and northern Vietnam.

Sinogastromyzon spp. have specialised morphology adapted to life in fast-flowing water. The paired fins are orientated horizontally, head and body flattened, and pelvic fins fused together.

These features form a powerful sucking cup which allows the fish to cling tightly to solid surfaces. The ability to swim in open water is greatly reduced and they instead ‘crawl’ their way over and under rocks.

The family Balitoridae as recognised by Kottelat (2012) is widely-distributed across much of the Indian subcontinent, Southeast Asia and China.

Kottelat (2012) also considers the family Gastromyzontidae valid and many former balitorids are now contained within that group, but Sinogastromyzon is retained in Balitoridae.

Thanks to Dr. T-Y Liao.

References

1. Chen, I-S. and Y-C Chang, 2005 - The Sueichan Press, Keelung, Taiwan: 1-284
   A Photographic Guide to the Inland-water Fishes of Taiwan. Vol.1 Cypriniformes.
2. Kottelat, M., 2012 - Raffles Bulletin of Zoology Supplement 26: 1-199
   Conspectus cobitidum: an inventory of the loaches of the world (Teleostei: Cypriniformes: Cobitoidei).
3. Kottelat, M. and X. L. Chu, 1988 - Revue Suisse de Zoologie 95(1): 181-201
   A synopsis of Chinese balitorine loaches (Osteichthyes: Homalopteridae) with comments on their phylogeny and description of a new genus.
4. Lee, T-W, 2000 - Endemic Species Research 1: 13-20
   Distribution and Relative Abundance of Sinogastromyzon puliensis in Taiwan.
5. Liao T-Y., C-C. Pan and C-S. Tzeng, 2008 - Ichthyological Exploration of Freshwaters 19(3): 193-200
   Migration of Sinogastromyzon puliensis (Teleostei: Balitoridae) in the Choshui River, Taiwan.
6. Liao, T-Y., T-Y. Wang, H-D. Lin, S-C. Shen, and C-S. Tzeng, 2008 - Zoological Studies 47(4): 383-392
   Phylogeography of the Endangered Species, Sinogastromyzon puliensis (Cypriniformes: Balitoridae), in Southwestern Taiwan Based on mtDNA.
7. Liu, S-W., X-Y. Chen, and J-X. Yang, 2010 - Environmental Biology of Fishes 87(1): 25-37
   Two new species and a new record of the genus Sinogastromyzon (Teleostei: Balitoridae) from Yunnan, China.
8. Wu, F-C. and T-W. Lee, 2002 - River Research and Applications 18(2): 155-169
   Effect of flow-related substrate alteration on physical habitat: a case study of the endemic river loach Sinogastromyzon puliensis (Cypriniformes, Homalopteridae) downstream of Chi-Chi Diversion Weir, Chou-Shui Creek, Taiwan.
9. Yu, S-L. and T-W Lee, 2002 - Zoological Studies 41(2): 183-187
   Habitat Preference of the Stream Fish, Sinogastromyzon puliensis (Homalopteridae).