This study aimed to further understanding Coilia nasus germplasm resources, regarding aspects of cellular inheritance and biochemical inheritance, chromosome number, and karyotype structure of C. nasus, and to lay a theoretical foundation for screening the biochemical genetic markers of C. nasus germplasm. Short-term in vitro culture of gill filament cells was used to prepare chromosome specimens. Polyacrylamide gel electrophoresis was used to detect the expression of lactate dehydrogenase (LDH) in the heart, liver, kidney, eye, muscle, gill of C. nasus. The results showed that there was no difference in the number of chromosomes between males and females. The number of chromosomes was 2n=48, all of which belonged to terminal centromeric chromosomes (t), and the karyotype was 2n=48t. The number of arms (NF) was 48, and the sex chromosome type was ZW/ZZ. Unlike previous studies in which the karyotypes of C. nasus and C. brachygnathus were ZO/ZZ type, we found a “point” in the metaphase mitotic phase of the female chromosomes of C. nasus. Using mode analysis, we found that the probability of distribution of this “point” was more than 90.8% (120 metaphase mitotic phases), which was confirmed to be the female heteromorphic sex chromosome of Coilia species. A total of six LDH isoenzyme bands were detected in six tissues of C. nasus (heart, liver; kidney; eye, muscle; gill.), among which six bands were found in the liver tissue, with the lowest activity, and five bands were found in other tissues, with different activities. The expression of the LDH isoenzyme of C. nasus was tissue-specific. There were differences in LDH activity of C. nasus among different populations, in addition to individual differences. LDH is widely distributed in C. nasus and has obvious tissue specificity. The LDH enzyme band corresponding to expression in the eyes was highly expressed and presented stable activity, owing to which it can be used as a biochemical genetic marker for the identification of germplasm characteristics of C. nasus.