Rasboroides vaterifloris - Fire Rasbora

Cyprinidae

Endemic to southwestern Sri Lanka where it is restricted to the Kalu, Bentota, Gin and Nilwala river basins. Sadly like many other Sri Lankan endemic species some wild populations of the species are thought to be under threat of habitat loss through deforestation or pollution from agricultural chemicals while others are considered to be at risk of overfishing for the aquarium trade. It is currently listed as "Lower Risk: conservation dependent" on the IUCN Red List of Threatened Species and is considered to be officially endangered by the Sri Lankan government. Only between 1.5 to 3% of the island's original rainforest remains and deforestation is continuing at an alarming rate. The organisation Rainforest Rescue International (www.rainforestrescue.org.au) continues to work on various conservation projects with the hope that what remains of Sri Lanka's tremendous biodiversity can be preserved.

Inhabits shady, slow-moving forest streams. These tend to have thick marginal vegetation with dense rainforest canopy above. The substrate is most often composed of a thick layer of silt littered with fallen tree branches and leaf litter and the water is quite clear but coloured weakly brown due to tannins released from the decomposing organic matter.

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 group.

Choice of decor 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. These tiny creatures 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 such as this. Certainly Rasboroides vaterifloris is known to display more intense colouration in tannin-stained water. Leaves can be left in the tank to break down fully or removed and replaced every few weeks. Alder cones also make a useful and attractive addition to the base of the set-up.

Allow the wood and leaves to stain the water. A small net bag filled with aquarium-safe peat can also be added to the filter or hung over the edge of the tank to aid in the simulation of black water conditions. Alternatively obtain some genuine peat fibre and simply drop a few handfuls into the tank. This will become completely saturated with water after a few days and sink to the bottom where it can look really effective. Provided a good routine of water maintenance is practiced no adverse effects should occur using either peat or leaves in an aquarium.

Fairly dim lighting is also preferable. You could add some aquatic plants that can survive under such conditions such as Microsorum pteropus, Vesicularia dubyana or perhaps some potted Cryptocorynes. A few patches of floating vegetation would be really useful to diffuse the light entering the tank too. Filtration does not need to be particularly strong as it mostly hails from sluggish waters and may struggle if there is a fast current in the tank.

This species can be a little tricky to acclimatise to aquarium life as it often arrives in poor condition and seems to be rather sensitive to swings in water chemistry. As a result it should not be introduced to biologically immature aquaria and small, regular water changes of around 10% tank volume are the ideal in terms of maintenance.

77 - 84°F/25 - 29°C

6.0 - 7.0. It will fail to thrive in alkaline water.

2 - 8°H

Stomach analyses of wild specimens have revealed it to be primarily a micropredator feeding on small insects and organic detritus. In the aquarium it will normally 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.

Not really suitable for most community tanks as it has a retiring nature and may be intimidated or outcompeted for food by larger/more boisterous tankmates. Small, peaceful cyprinids such as Trigonostigma or Boraras species make good choices and we suspect it will also do ok with many small South American characins, Otocinclus or pygmy Corydoras catfish. Accommodating it in a biotope-style community of Sri Lankan fish is more tricky although suitable species that occur sympatrically with it in nature include Malpulutta kretseri , Pseudosphromenus cupanus and Puntius titteya .

It's a schooling species by nature and really should be kept in a group of at least a dozen specimens. Maintaining it in decent numbers will not only make the fish 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.

The female is much the larger of the two sexes. By comparison the male is a slighter, more brightly-coloured fish.

This species is notoriously tricky to breed although certainly not impossible. Like many small cyprinids it 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 and a breeding tank measuring around 18" x 10" x 10"/45cm x 25cm x 25cm/29.5 litre or similar should be set up. Peat fibre (NOT the peat moss available at most garden centres) is an ideal substrate as it replicates the silty conditions of the species' natural streams and helps to provide the correct water chemistry. It will also act as a safeguard against the adults eating all the eggs. A couple of good-sized clumps of Java moss will provide cover and security for the fish as well as an alternative spawning medium. The water should be of pH 6.0-6.5, gH 3-4 with a temperature towards the upper end of the range suggested above. Filtration should be very gentle and an air-powered sponge-type unit is best as it will not suck in eggs or fry.

According to most reports it is best spawned in a group of 5 to 6 well-conditioned adult pairs. These are added to the breeding tank and left to spawn in situ for 4 or 5 days before being removed. Eggs are usually deposited in small batches of around 20 and several spawning events normally occur before a female is spent. The fry can then be reared in the same tank and some breeders recommend reducing the water level to around 4"/10cm at this point.

Incubation is temperature-dependant to an extent but usually takes between 24 and 48 hours with the young free-swimming after 3-5 days. Initial food should be Paramecium or similar introducing Artemia nauplii and/or microworm once the fry are large enough to accept them. They are said to be slow-growing and take several months to reach maturity.

This species may also be seen on sale as 'pearly rasbora', 'vateria flower rasbora' or 'Singhalese fire barb' and is not a common species in the aquatic trade. As far as we know it is not yet being produced commercially in any great numbers and its rather delicate nature means that problems often arise during shipping. Restrictions on exports of wild fish from its native Sri Lanka have also limited its availability. It is really only recommended to experienced aquarists but when maintained correctly arguably ranks among the most beautiful small cyprinids available in the hobby.

Depending on collection locality the fish vary considerably in colour with the red, orange and yellow-finned forms being particularly sought after. The colour of the body can also differ from red/orange to blue. There were four subspecies described in the 1950s (when the species was still considered a Rasbora) based on these variations; R. v. vaterifloris from the Kalu river, R. v. ruber from the Bentota river, R. v. pallida from the Gin river and R. v. rubriculis from the Nilwala river. These are still regarded as such by some authorities although it is widely accepted that they represent variants of Rasboroides vaterifloris due to a lack of type material hindering conclusive study. The name R. nigromarginata has also been used to refer to a red form that is said to differ in some morphological aspects but is currently considered a synonym of Rasboroides vaterifloris.

Brittan assigned this species to the subgenus Rasboroides in 1954 but it was not until 1993 that Maurice Kottelat elevated it to full genus level. This change has not yet been recognised by all authorities and it is still referred to as Rasbora vaterifloris by the majority of western hobbyists. A 2007 phylogenetic study confirmed that it should be included in a separate genus as it shows a large enough degree of genetic divergence from other Sri Lankan rasboras such as R. caverii and R. wilpita  to be considered as such, splitting away from the lineage around 8.6 million years ago whereas the other two shared a common ancestor up to 1.6 mya. The genus is currently monotypic.

Several captive breeding initiatives have been set up in order that that Rasboroides vaterifloris can be produced commercially for the aquatic trade. Unfortunately reports suggest that the more highly-coloured fish are becoming scarcer and there is a distinct possibility that selective collections for the aquatic trade have altered the structure of the species' wild populations. Juvenile fish also tend to be returned to the water with only the adults being collected and many of these die before even reaching an aquarium shop due to poor handling techniques. According to Pethiyagoda (1991) only around 10% of the fish collected end up in hobbyists' tanks.

Literature cited

1. Mayden, Richard L.; Tang, Kevin L.; Conway, Kevin W.; Freyhof, Jörg; Chamberlain, Sarah; Haskins, Miranda; Schneider, Leah; Sudkamp, Mitchell; Wood Robert M.; Agnew, Mary; Bufalino, Angelo; Sulaiman, Zohrah; Miya, Masaki; Saitoh, Kenji; He, Shunping. 2007 - J. Exp. Zool. (Mol. Dev. Evol.) 308B: 1–13.
   Phylogenetic relationships of Danio within the order Cypriniformes: a framework for comparative and evolutionary studies of a model species.
2. KOTTELAT, M. 1999 - Raffles Bull. Zool. 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. www.fishbase.org
4. Ekaratne, S. U. K. 2000 - Yadava, Y. S.,Ed. Bay of Bengal Programme BOBP/REP/88. Chennai, India.
   A Review of the Status and Trends of Exported Ornamental Fish Resources and Their Habitats in Sri Lanka.