The morphometric and meristic characters ofOsteobrama cotio (Ham.) have been studied and the results have been discussed. The change in the relative position of dorsal and pelvic fins at different size groups of this fish has been reported for the first time. Regression of predorsal and prepelvic lengths revealed the origin of dorsal fin in front of pelvic fins below 17·5 mm size groups, whereas in fishes with total length more than 17·5 mm dorsal fin was located behind the pelvic fins. The mathematical relationships of various parameters have been described. The ratios of different body parts with total length and those of head region with head length, have been replaced by percentage values. An attempt has been made to revise the description ofO. cotio (Ham.) for the purpose of identification.