Rasboroides vaterifloris (Deraniyagala, 1930)
Pearly rasbora
photo by Terceira, A.C.

Family:  Danionidae (Danios), subfamily: Rasborinae
Max. size:  4 cm TL (male/unsexed)
Environment:  benthopelagic; freshwater; pH range: 6 - 6; dH range: 5 - 8
Distribution:  Asia: restricted to the Kalu basin, Sri Lanka.
Diagnosis:  Dorsal soft rays (total): 10-10; Anal soft rays: 8-9; Vertebrae: 29-29. Rasboroides vaterifloris is distinguished from its congener R. nigromarginatus by the location of pelvic-fin origin which is midway between the pectoral-fin base and anal-fin origin (vs. closer to anal-fin origin), by having the dorsal margin of the operculum more or less straight (vs. with a deep indentation), and the dorsal profile of the head approximately straight (vs. slightly concave) behind the level of the eye in males. Males of R. vaterifloris can be diagnosed from those of R. nigromarginatus by having a greater interorbital width (29-33 % HL, vs. 17-22) and a greater internarial width (19-21 % HL, vs. 11-17), while females differ by having a greater anal-fin depth (23.5-24.8 % SL, vs. 17.4-22.7), a greater interorbital width (25-33 % HL, vs. 16-21), a greater caudal-peduncle depth (12.4-13.4 % SL, vs. 10.4-12.3) and a lesser caudal-peduncle length (18.6-21.2 % SL, vs. 21.1-25.0). It differs from R. pallidus and R. rohani by having the dorsal-fin origin 1 scale-width (vs. 3 scale-widths) behind the pelvic-fin origin and a lesser body depth of 31.0-32.8 % SL (vs. 33.0-37.5 in R. pallidus and 33.3-40.0 in R. rohani) (Ref. 94541).
Biology:  Occurs in shallow, cool, clear, quiet, heavily shaded forest streams, usually with a silty substrate and often in areas with a large amount of leaf debris in the water. Feeds on terrestrial insects (Diptera and Coleoptera, see Ref. 6469) and detritus. Males slimmer and brightly colored than females.
IUCN Red List Status: Endangered (EN); Date assessed: 05 August 2019 (B1ab(iii)+2ab(iii)) Ref. (130435)
Threat to humans:  harmless
Country info:   
 


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