Gynogenesis is a form of asexual reproduction, where individuals (females) produce their clonal offspring, but yet depend on sperm of related sexual species to stimulate egg development. The mating complexes of gynogenetic species and their sexual relatives are seen in many fishes and amphibians. In theory, however, such gynogenetic-sexual complexes should not be stable or long-lived. Theory predicts that, all else being equal, gynogens predominate in the system with the two-fold advantage of producing no males and this ultimately causes the extinction of the sexual hosts and consequently the gynogens themselves. Growth can be a factor that facilitates the persistence of gynogenetic-sexual complexes if the sexual species has higher growth rate (and therefore greater fecundity) than the gynogens. Here I examined this potential scenario in the system of the gynogenetic polyploid (mostly triploid and less frequently tetraploid), ginbuna Carassius auratus langsdorfii and the sexual diploid, nagabuna C. a. burgeri, using data of a mixed-culture experiment in rice fields. Measurment of fish size and determination of ploidy showed that, contrary to expectation, the sexual C. a. burgeri was smaller than the gynogenetic C. a. langsdorfii. Therefore, I conclude that growth is not a factor that contributes to the coexistence of the gynogenetic and sexual Carassius species.