Notopterus notopterus (Pallas, 1769)
Species overview
As other members of its family it shows the body shape of a "knife fish", i. e. the anal fin is extremely long and merges in the tail fin, but it still has pelvic fins and a dorsal fin. In coloration quite variable from silvery to black without distinct patterns, except for countershading and a white tip of the dorsal fin;
Size observed: 60 cm
Taxonomic description
-Body shape knife like, laterally compress, greatest depth slightly posterior to origin of anal fin; upper profile of head straight to feebly concave, underside of head feebly convex; outline of back curved, outline of belly rather straight.
-Head length about 1/5 of body length, mouth terminal, edge of mouth extending to below posterior rim of eye.
-Eye large with golden iris. Preopercle with 6-8 scale rows of scales larger than scales of body; opercular cleft long, mergin in underline of head.
-Pectoral fin rather long, its origin at level of edge of mouth, in length extending beyond origin of anal fin, 15-17 fin-rays.
-Pelvic fins small, their origin behind middle of pectoral fin.
-Anal fin 99-111 fin rays, caudal fin externally hardly to separate from anal, with reduced skeleton, 13-17 fin-rays. 67-74 vertebrae.
-Coloration, adult and subadult usually uniformly silvery, greyish or dark, large specimens pale or dirty white, brillantly silvery, golden greyish, olivaceous to nearly black; depending on water quality. Very young specimens with dark vertical bars.
Type locality
Gymnotus notopterus:>Indian Ocean<, Notopterus kapirat >Amboina<, Notopterus kapirat >Malabar and China<, Mystus badgee >Mola Mola river at Poona, Beema river at Seedalaik<, Notopterus pallasii >India<, Notopterus bontianus >Irrawaddy and Java<, Notopterus primaevus , a fossil, >Padang, Sumatra, freshwater Tertiary lignite<,
Distribution
South and Southeast Asia: Main river basins of India; peninsular Thailand and Malaysia, Vietnam (?), Sumatra, Java; not Borneo.