The determination of fish age and growth of Nemiplerus japonicus is fundamental in fisheries biology population studies. Age studies can furnish other basic data such as stock age structure, age at first maturity, spawning frequency, individual and stock responses to changes in the habitat, recruitment success, etc. Age and growth data also permit the determination of population changes due to fishing rates. Because a scale holds the growth history of the fish, it can also be used to determine length at all ages up to the current one. The present study results were showed that the fishes of ages 1, 1+, 2, 2+, 3, 3+, and 4, when the age level was increased, the length also increases but fish weight remains stable during ages 1+ and 2 and increase is seen only after age 3. The age of fish may be determined by various methods depending upon their suitability to the species concerned. In certain cases more than one method may be employed chiefly to verify the results obtained by the other. Overall the fish age and growth study is giving valuable information of fish populations.