Matt Clarke looks at one of the largest species of Rasbora, which has just turned up in imports from south Asia.
Common name: Yellowtail rasbora
Scientific name: Rasbora tornieri Ahl, 1922
Origin: This species has been reported from Indonesia, Malaysia, Thailand and Brunei Darussalam.
Size: Very large for a Rasbora. Some museum specimens measure around 17cm/7".
Water: Ideally, soft and acidic water, but seems adaptable to harder, more alkaline conditions. Many Rasbora are sensitive when first imported, so check that any fish you buy have been well quarantined and acclimated to your local water conditions.
Diet: This fish lives just below the water surface and feeds on terrestrial insects.
Aquarium: According to Kottelat et al. 1993, tornieri is found in the surface waters of ditches, streams, canals and lowland floodplains. It is said to enter ponds and rivers to spawn when flooding occurs between May and June. It's a peaceful fish and should be kept in a large group (a minimum of six) in a spacious well-filtered aquarium alongside other placid species. Due to its large size, a tank of 120cm/48" ought to be the minimum to maintain a shoal of these fish. Rasbora, as a sweeping generalisation, don't like pollution, so you'll need to keep the tank well maintained and conduct plenty of water changes to keep these in good health.
Identification: Rasbora dusonensis and R. tornieri both reach over 12cm/5" and have a similar longitudinal stripe and a black edge to the caudal fin. R. dusonensis, according to Bleeker, should have a reddish caudal, while that of tornieri is more yellow. However, somewhat confusingly, there are some slightly different colour forms seen in tornieri with yellow to orange tails. Scale counts are also slightly different between tornieri and dusonensis.
Availability: Rarely offered for sale. These ones were spotted on sale in the Spring of 2005 at the PFK award-winning Wildwoods Water Gardens (0208 366 0243).
Price: Expect to pay around the 4.00 mark.