A Shachihoko is a mythical animal from Japanese folklore with the head of a tiger/dragon and body of a fish. Shachihoko were said to be able to bring rain and grant protection from fire. For this reason, statues of shachihoko feature prominently on the rooftops of various castles, temples and other major buildings made of wood.
They may have evolved from a similar mythical Chinese animal called the Chiwen.
