(Sanskrit: “Fish”), first of the 10 avatars (incarnations) of the Hindu god Vishnu. In this appearance Vishnu saved the world from a great flood. Manu, the first man, caught a little fish that grew to giant size and revealed himself as the god. When the flood approached, Manu saved himself by tying his boat to the horn on the fish's head. Some early accounts refer to the fish-saviour as Prajāpati (whose identity is later merged with that of Brahmā), an illustration of how the legends of the avatars incorporate existing myths.

Matsya may be depicted either in animal form or in a combined human-animal form. In the latter case the man is shown as the upper half, and the fish as the lower half. Matsya is generally represented with four hands, one holding the conch shell, one the discus (chakra), one in the pose of conferring a boon (varada-mudrā), and one in the protection-affording pose (abhaya-mudrā). According to the canons of sculpture, the man-half should be shown as wearing all the ornaments usually associated with Vishnu.