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Brevibora cheeya LIAO & TAN, 2011

Classification

Order: Cypriniformes Family: Cyprinidae

Distribution

Recorded from the states of Selangor, Terengganu, Pahang and Johor in Peninsular Malaysia, Jambi and Riau provinces in Sumatra (Indonesia) and the island of Banka which lies off Sumatra’s southeastern coast. Type locality is ‘Terengganu, Rantau Abang, 56 kilometers to Kuala Terengganu, Malaysia’.

Habitat

The type locality is described as flowing slowly through ‘coastal heath forest’ among stands of a Melaleuca species (myrtle). The substrate was a mixture of sand and peat and the water acidic (pH 4.5 in February 2009).

Fish diversity was high with sympatric species including Boraras maculatus, Cyclocheilichthys apogon, Osteochilus spilurus, Parachela maculicauda, P. oxygastroides, Rasbora einthovenii, R. trilineata, ‘Puntius‘ johorensis, Trigonopoma gracile, T. pauciperforatum, Lepidocephalichthys furcatus, Pangio alcoides, P. semicincta, Kryptopterus macrocephalus, Ompok leiacanthus, Wallago leerii, Hemibagrus nemurus, Pseudomystus leiacanthus, Clarias batrachus, C. meladerma, Parakysis verrucosa, Aplocheilus panchax, Hemirhamphodon pogonognathus, Monopterus albus, Nandus nebulosus, Pristolepis grooti, Belontia hasselti, Betta imbellis, B. waseri, Luciocephalus pulcher, Parosphromenus paludicola, Trichopodus leerii, T. trichopterus, Trichopsis vittata, Channa bankanensis, C. lucius and C. striata.

Maximum Standard Length

40 – 55 mm.

Aquarium SizeTop ↑

A tank with a footprint of 60 ∗ 30 cm is just about big enough to house a small group.

Maintenance

Choice of décor is not as critical as water quality although this species does look particularly effective in a well-planted tank with a dark substrate. To see it at its best a biotope-style set-up can also make an interesting project. A soft, sandy substrate is probably the best choice to which can be added a few driftwood roots and branches, placed in such a way that plenty of shady spots are formed. If you can’t find driftwood of the desired shape common beech or oak is safe to use if thoroughly dried and stripped of bark.

The addition of dried leaf litter (beech, oak or Ketapang almond leaves are all suitable; we like to use a mixture of all three) would further emphasise the natural feel and as well as offering even more cover for the fish brings with it the growth of microbe colonies as decomposition occurs. Such microorganisms can provide a valuable secondary food source for fry whilst the tannins and other chemicals released by the decaying leaves are thought to be beneficial for blackwater fish species. Leaves can be left in the tank to break down fully or removed and replaced every few weeks.

This species will do best under fairly dim lighting. You could add some Asian plants that can survive under such conditions such as Microsorum pteropus, Taxiphyllum barbieri or perhaps some potted Cryptocorynes. A few patches of floating vegetation would be really useful to diffuse the light entering the tank too.

Water Conditions

Temperature: 20 – 25 °C

pH: 4.0 – 7.0

Hardness: 0 – 143 ppm

Diet

Likely to be a micropredator feeding on small insects, worms, crustaceans and other zooplankton in nature. 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 or Artemia along with good quality flakes and granules will result in the best colouration and encourage the fish to come into breeding condition.

Behaviour and CompatibilityTop ↑

This species makes an ideal addition to a peaceful community of Southeast Asian/Indian fishes which could include similarly-sized, peaceful rasboras, barbs, botiid/cobitid loaches, and gouramis of the genus Trichogaster, but will not compete well with much larger or more boisterous species. SF member Steve Grant, one of the few to have maintained and written about (see ‘notes’) it, noted that it acted aggressively towards the similar-looking but smaller R. dorsiocellata whilst leaving other tankmates alone.

It’s a schooling species by nature and in the unlikely event that a group 8-10 specimens becomes available their purchase will result in a more effective, natural-looking display. Males should also exhibit their best colours as they compete with one other for female attention.

Sexual Dimorphism

Mature females are noticeably rounder-bellied and probably a little larger than males.

Reproduction

We’re unsure if it has been bred in the hobby although it should certainly be possible. Like most 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 in a densely-planted, mature aquarium it is possible that small numbers of fry may start to appear without human 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 separate, perhaps 20-30 litre, containers should also be set up. These should be very dimly lit with the base either left bare or covered with some kind of mesh of a large enough grade so that any eggs that fail to adhere to the plant can pass through but small enough so that the adults cannot reach them.

The widely available plastic ‘grass’-type matting can also be used and works very well for related species. The water itself should be of slightly acidic to neutral pH with a temperature towards the upper end of the range suggested above. An internal power filter can be added initially and this should be positioned so that the flow is directed down the full length of the tank.

When the adult fish are well-conditioned and the females appear full of eggs one or two pairs should then be introduced to each container. Spawning can be initiated by adding small amounts of cool water every few hours in such a way that the tank is gradually topped up and feeding small amounts of live and frozen foods. Several spawning events normally occur before a female is spent of eggs.

The adults will likely eat any eggs they find and are best removed after a couple of days at which point the power filter should be switched for a mature sponge-type unit in order to avoid fry being sucked into the mechanism. Incubation in related Rasbora spp. is temperature-dependant to an extent but usually takes between 18 and 48 hours with the young free-swimming 24 to 48 hours later. Initial food should be Paramecium or similar introducing Artemia nauplii and/or microworm once the fry are large enough to accept them.

NotesTop ↑

This species is very rare in the trade and is normally imported only as bycatch among shipments of other fishes. It can be told apart from B. dorsiocellata, the only other member of the genus at present, by a combination of characters as follows: lateral line complete (25-30 pored scales vs. 4-9); more scales in the lateral row (29-32 vs. 25-27); larger adult size (39.0 mm SL vs. 23.0 mm SL); larger head and prepectoral length (head length 28.5-30.0% SL, vs. 24.4-27.9; prepectoral length 29.6-32.9% SL, vs. 25.8-28.8).

Several years prior to description Grant (2002) suggested that specimens of B. cheeya in the aquarium trade might represent the subspecies Rasbora dorsiocellata macrophthalma (Meinken, 1951) which was described using a specimen from the aquarium trade and the vague locality ‘Malay Peninsula’. Liao and Tan (2011) argue out that the type specimen of R. d. macrophthalma has been lost and that even if proved a genuine species the validity of B. cheeya would be unaffected since it possesses a complete lateral line (vs. incomplete in R. d. macrophthalma).

The genus can be distinguished by the following combination of characters: palatine process rectangular with a narrow base and lacking projection; a median black blotch in the dorsal fin; low number of predorsal vertebrae (8-9, 6:3 vs. more than 9 in other rasborin genera).

Rainboth’s ‘Fishes of the Cambodian Mekong’ characterised members of Rasbora by possession of an unbranched, non-spiny first dorsal fin ray and seven soft dorsal rays, origin of the dorsal fin in the middle of the body, five branched anal fin rays, a small mouth not extending below the eye and a lack of barbels. It’s long been recognised as a polyphyletic lineage and Liao et al. (2010) proposed a number of taxonomical changes based on the results of their phylogenetic analysis.

The authors found species of rasborin genera to represent a monophyletic grouping existing in six clades, and erected four new genera (all containing former members of Rasbora) in order to preserve monophyly of the existing groups, i.e., Boraras, Horadandia, Rasbora, Rasboroides and Trigonostigma.

The first clades is monotypic, comprising only Kottelatia brittani (formerly Rasbora brittani) while the second contains the genus Brevibora. The third clade comprises Boraras, Horadandia, Rasboroides, Trigonostigma and three species previously included in Rasbora but moved into new genera; Trigonopoma gracile, T. pauciperforatum and Rasbosoma spilocerca. The results for Boraras and Trigonostigma were found to be inconclusive in some respects and further work regarding their phylogenetic position was recommended.

The fourth clade includes Rasbora semilineata, R. borapetensis, R. rubrodorsalis and an undescribed fish similar to R. beauforti. Clade five consists of R. daniconius, R. hubbsi, R. paucisqualis, R. wilpita, R. kobonensis, R. ornata and R. cf. daniconius. Clade six, meanwhile, is subdivided into two groupings.

The first contains R. einthovenii, R. elegans and R. cephalotaenia and the second R. lateristriata, R. argyrotaenia, R. volzii, R. paviana, R. rasbora (plus an undescribed, similar fish), R. caudimaculata and R. trilineata. As this final clade contains the type species (see below) its members retain the generic name Rasbora as do clade five species because they don’t differ sufficiently to warrant the erection of a new genus/genera.

Unfortunately many species weren’t included in the analysis, meaning inevitable questions are raised regarding the correct placement of the 40 or so other Rasbora spp., in particular. As the genus had previously been split into various ‘species groups’ (groups of closely-related species) dating back to Brittan (1972, who referred to them as ‘species complexes’) Liao et al. proposed the following arrangement whilst noting it may be subject to change with further phylogenetic studies:

R. semilineata species group: R. semilineata, R. borapetensis, R. rubrodorsalis.
R. trifasciata species group: R. trifasciata, R. amplistriga, R. bankanensis, R. dies, R. ennealepis, R. hubbsi, R. johannae, R. meinkeni, R. paucisqualis, R. rutteni, R. sarawakensis, R. taytayensis, R. tobana, R. tuberculata.
R. daniconius species group: R. daniconius, R. caverii, R. kobonensis, R. labiosa, R. ornata, R. wilpita.
R. einthovenii species group: R. einthovenii, R. cephalotaenia, R. elegans, R. jacobsoni, R. kalochroma, R. kottelati, R. nematotaenia, R. tubbi.
R. argyrotaenia species group: R. argyrotaenia, R. aprotaenia, R. aurotaenia, R. baliensis, R. borneensis, R. bunguranensis, R. dusonensis, R. evereti, R. hobelmani, R. hossi, R. lateristriata, R. laticlavia, R. leptosoma, R. philippina, R. septentrionalis, R. spilotaenia, R. steineri, R. tawarensis, R. tornieri, R. volzii.
R. sumatrana species group: R. sumatrana, R. atridorsalis, R. calliura, R. caudimaculata, R. dorsinotata, R. notura, R. paviana, R. rasbora, R. subtilis, R. trilineata, R. vulgaris.

Not classified: R. beauforti, R. chrysotaenia, R. gerlachi (validity in question), R. kalbarensis, R. reticulata, R. vulcanus (possibly not Rasboras) and R. zanzibarensis (identity in question).

Shortly afterwards a paper investigating systematics of the subfamily Danioninae was published (Tang et al. 2010) with significantly different results. The four new genera proposed by Liao et al., plus Boraras and Trigonostigma, were synonymised with Rasbora based on an incomplete knowledge of relationships within the group, an approach described as ‘more conservative’. Though perhaps neither conclusion is satisfactory we decided to adopt the system of Liao et al. pending future studies, if only because Boraras and Trigonostigma are well-known genera in the aquarium hobby.

The identity of the type species, often given as R. rasbora in the past, is no longer in question; when Bleeker first referred to the name Rasbora in 1859 only four nominal members were included of which R. cephalotaenia (known as Leuciscus cephalotaenia at the time) should be considered the type. Howes (1980) suggested the separation of a number of species into the new genus Parluciosoma with type species P. (Rasbora) argyrotaenia but the monophyly of that grouping was not recovered in phylogenetic analyses.

Thanks to Steve Grant.

References

1. Grant, S., 2002 - BSSW Report Heft 4(2002): 13-17
   Zur Identität und Gültigkeit von Rasbora macrophthalma MEINKEN, 1951 (Cyprinidae, Rasborinae).
2. Kottelat, M., 1999 - Raffles Bulletin of Zoology Supplement 47(2): 591-600
   Nomenclature of the genera Barbodes, Cyclocheilichthys, Rasbora and Chonerhinos (Teleostei: Cyprinidae and Tetraodontidae), with comments on the definition of the first reviser.
3. Liao, T-Y., and H. H. Tan, 2011 - Raffles Bulletin of Zoology 59(1): 77-82
   Brevibora cheeya, a new species of cyprinid fish from Malay Peninsula and Sumatra.
4. Liao, T. Y., Kullander, S. O. and F. Fang, 2010 - Zoologica Scripta 39(2): 155-176
   Phylogenetic analysis of the genus Rasbora (Teleostei: Cyprinidae).
5. Mayden, R. L., K. L. Tang, K. W. Conway, J. Freyhof, S. Chamberlain, M. Haskins, L. Schneider, M. Sudkamp, R. M. Wood, M. Agnew, A. Bufalino, Z. Sulaiman, M. Miya, K. Saitoh, and S. He, 2007 - Journal of Experimental Zoology, Molecular Development and Evolution 308B: 1–13
   Phylogenetic relationships of Danio within the order Cypriniformes: a framework for comparative and evolutionary studies of a model species.
6. Tang, K. L., M. K. Agnew, W. J. Chen., M. V. Hirt, T. Sado, L. M. Schneider, J. Freyhof, Z. Sulaiman, E. Swartz, C. Vidthayanon, M. Miya, K. Saitoh, A. M. Simons, R. M. Wood and R. L. Mayden, 2010 - Molecular Phylogenetics and Evolution 57(1): 189-214
   Systematics of the subfamily Danioninae (Teleostei: Cypriniformes: Cyprinidae).