Monday, May 1, 2017

Black-lined Golden Rasbora (Rasboroides nigromarginatus)


English: Black-lined Golden Rasbora
Binomial: Rasboroides nigromarginatus
Sinhala: කළු වරල් හල්මල් දණ්ඩියා[Kalu waral halmal dandiya]

Rasboroides nigromarginatus is a relatively rare endemic species of freshwater fish restricted to the Kalu river basin. This species was described for the first time by a Germen biologist named H. Meinken in 1957 after observing a single specimen of the fish among some exported ornamental fresh water fishes from Sri Lanka. Since the exact collected location has not been known, he has mentioned ‘Ceylon’ as the locality. Meanwhile, the species remained in the synonymy of R. vaterifloris for a long time. It has not been observed in the natural environment since then until R. Pethiyagoda & K. Manamendra Arachchi observed some fish from Athwelthota area in 1994 that match with the H. Meinken’s first description. Again in 2010, members of Wildlife Conservation Society, Galle have found and observed the same fish from Athwelthota area and have re-described the fish as a valid species by verifying Meinken’s work(Batuwita S. et al., 2013). 
Above photographed ones were also observed in river Maguru, which is a branch of Kalu river. Observed place was a shady place of the river margin close to the borders of Sinharaja forest. Place was away from human habitats and no activities were observed that cause environmental pollution, which might be the reason to have a healthy living population of this rare fish. Since the population of the fish is restricted to few locations, critical actions need to be taken to protect the species for the future. 

  • Batuwita S., de Silva M. and Edrisinghe U., 2013. A review of the danionine genera Rasboroides and Horadandia (Pisces: Cyprinidae), with description of a new species from Sri Lanka Ichthyol. Exploe. Freshwaters, Vol. 24, No. 2, 121-140 pp.