Roofs of Japanee traditional houses are generally covered with ceramic tiles called Kawara (瓦) and these are often decorated with the decorative ornaments like Shachihoko (鯱).
These decorave ornaments often have meanings like keeping away bad spirits, to protect the house etc.
This fish like creature is called Shachihoko (鯱）, which is an imaginary creature. The Shachihoko has a face of tiger and a fish body and it has been believed that in case of fire, the Shachihoko extinguish the fire with water emitted from the mouth.
Old Japanese castles generally have the Shachihoko on the both ends of roof.
He is called Daiku (大黒) and is a member of the Seven Deities of Good Fortune (七福神）. He is a god of food and good fortune, sitting on a bags of rice and carring a large bag which is a full of fortune and also carring the fortune hanmer.
The next guy is called Ebisu(恵比寿).
He is also a member of the Seven Deities of Good Fortune (七福神）and he is a god of business.
They are generally put on a roof to decorate the house and to protect those people living in there.
They can also be used for decorating your garden or balcony and can also be used as an interior decoration.
You can check the sizes and prices of these ornaments on my online store
You can also see the actual ornaments at my store
MA by So Shi Te
2-22-15 Minamiaoyama, Minato-ku,
Tokyo Japan 107–0062
The shop is only 1min walk from Gaienmae station exit 1b on Ginza line.