Reproduction A. Sexual maturity. Fishes can become sexually mature at various ages, depending on species. Several factors influence sexual maturity, including age, gender, and size. Although female dwarf perch receive sperm soon after they're born, they do not bear young for up to a year. Some bony fishes become sexually mature shortly after birth.
Most bony fishes become sexually mature between one and five years.
It may take ten years or more for some bony fishes to become sexually mature. In general, species of a small maximum size begin reproducing at an earlier age than those with a large maximum size. Age and associated size are major factors in determination of adulthood. B. Reproductive modes. In most species of bony fishes, sperm and eggs develop in separate male and female individuals.