This is ake nisai (new nisai...1 year 3-4 months). It is male. I have a few younger fish I bought to try and breed it maybe, but I think it is now too big. The new ones I have some are showing signs of this shape. Definitely not ryukin descent. Fed on whatever the koi are fed...wheatgerm pellets mainly and wall algae. The fish is now definitely much larger.