The Matsya motif for rangoli is common all over India. It is one of the most naturalistic positive symbols of fertility (shaped like yoni), abundance, conjugal happiness, providence and even a charm against the evil eye.
Fish are the easily gained food of all nations. As creatures of boundless liberty, not threatened by the flood, they appear as saviours in Indian myth, avatars of Vishnu and Varuna. In art, Matsya appears both zoomorphically (wholly fish) and anthropomorphically (with a human torso and the rear half of a fish).
Matsya is almost always listed as Vishnu’s first avatar, a fish-man who warns Manu, the first man, that there’s a flood coming, and that he should build a boat and load his family and some sages and animals seeds aboard. If you’re reading this and thinking “Noah’s Ark” you’re not alone, the world’s basically overflowing with flood myths, and they go back far enough that no one’s sure about the source, or if there even is one source.
Depicted here is the two golden fish (part of Ashtamangala) symbol originally representing the two main sacred rivers of India - the Ganga and Yamuna. These rivers are associated with the lunar and solar channels, which originate in the nostrils and carry the alternating rhythms of breath or prana.