Nishikigoi Pond comes with the special set bonus. When it is adjacent to other buildings belonging to the Cherry Garden Set, it will receive special bonuses.
The Nishikigoi Pond can be upgraded by Nishikigoi Pond Upgrade Kit item. To upgrade the Nishikigoi Pond, use the Nishikigoi Pond Upgrade item on the Nishikigoi Pond that is already situated in your city. Its upgraded version will then be placed directly on the same spot in your city and the production timer will not be reset. Note that the upgraded building will be from your current era, even if the old one was from one of the earlier ages.
Nishikigoi Pond will produce the following effects. Base effects will always be produced. Bonus effects are determined by how many other unique Cherry Garden Set buildings it is connected to.