Common Name/s: Platinum Ogon Scientific Name: Cyprinus carpio. Origin: Japan Maximum Size: 100 cm (39 inches;3.3 foot) Care: easy. Yamabuki Ogon Koi is a 1000+ gallon pond with a fine gravel substrate, rocks, and hardy plants. You will also need to provide adequate filtration to maintain proper water conditions. Feeding: high quality pellet or flake food with a protein content that does not exceed 30%. sex and breeding: Like most fish, koi reproduce through spawning in which a female lays a lot number of eggs and one or more males fertilize them. Nurturing the resulting offspring (referred to as fry) is a tricky and tedious job, usually done only by professionals. Although a koi breeder may carefully select the parents they wish based on their desired characteristics, the resulting fry will nonetheless exhibit a wide range of color and quality. Males are easily recognized by their concave anal section and occasionally by breeding spots on the head. Spawning may result in as many as 1,000 eggs, with fry emerging in approximately 4 to 7 days, depending on the water temperature. Feed fry small live foods or frozen dapnia for the first 3 to 4 weeks. At that time, gradually change their diet to crushed flake and pellet foods. Their color will emerge in about 3 to 12 weeks. Culled fry are usually destroyed (perhaps fed to other fish) and older culls are often sold as lower-grade "pond-quality" koi within their first year (also called "Tosai") at 3"â€“6" long. The semi-randomized result of the koi's reproductive process is both a blessing and a curse. While it requires diligent oversight to narrow down the favorable result that the breeder wanted all along, it also made possible the gradual transformation of wild river carp into the exquisite art form that we see in modern nishikigoi.