The purpose of this study is to examine fluctuating asymmetry of eye diameter, maxilla length, operculum length, and the number of pectoral fin ray and pelvic fin ray between ploidy and sex in diploid and triploid marine medaka, Oryzias dancena. In all experimental groups, eye diameter and maxilla length showed no significant difference between left side and right side (p>0.05). Results of operculum length in triploid male group and pectoral fin ray's number in diploid male group showed similarity ones with results of operculum length in triploid female group and pectoral fin ray’s number in diploid female group (p<0.05). However, the operculum length in diploid male group and pectoral fin ray's number in triploid male group showed consinderable difference with those of operculum length in diploid female group and pectoral fin in triploid female group. Findings of pelvic fin ray's number in all groups were similar to those of pectoral fin ray’s number in all groups (p<0.01).

We examined the morphometric characteristics and fluctuating asymmetry of diploid and triploid marine medaka, Oryzias dancena. We used morphometric parameters the truss and classical dimensions. Significant differences in all the classical and truss dimensions of the diploid and triploid fish. All the dimensions of the triploid fish were greater than those of the diploid fish. The triploid marine medaka shows sexual dimorphism in these characters, and the sexual dimorphism of the triploid marine medaka is similar to that of the diploid marine medaka. Thus, the growth of triploid marine medaka is faster than that of the diploid fish, and it displays clear sexual dimorphism, with male fish having longer dorsal and anal fins than female fish. we examined fluctuating asymmetry of eye diameter, maxilla length, operculum length, number of pectoral fin ray and number of pelvic fin ray. In all experimental groups, Eye diameter and maxilla length showed no significant difference between left side and right side (P>0.05). Trends of operculum length in triploid male group and pectoral fin ray's number in diploid male group showed similar trend with trends of operculum length in triploid female group and pectoral fin ray’s number in diploid female group. However, trends of operculum length in diploid male group and pectoral fin ray's number in triploid male group showed opposite trend with trends of operculum length in diploid female group and pectoral fin ray’s number in triploid female group. Trend of pelvic fin ray's number in all groups showed similar trend with trend of pectoral fin ray’s number in all groups.