Manu is the first man who survived the flood , all flood story is  similar because the flood of manu is first after that every one spread  the story in their region or city or country , According to research of  the Utnapistim in story of gilgamesh  we can say that the man who  survived is UMMANU . name is give by ( Theosophical Society )

Versions of the flood myth have been told by the Mayans, the Greeks, the Native Americans, the Africans, the Celts, The summer , The akkad , Australian Aborigines, the Chinese….the list goes on.

But the great flood of manu and matsya is very popular.

In the Hindu myth (first appearing in the Shatapatha Brahmana and later in the Puranas & the Mahabharata), Manu helps save a small fish, He then raises the fish, until it’s almost the size of the entire ocean.

The fish then transforms into Vishnu and saves him and  seven great sages from the deluge. Manu then marries and re-populates  the earth 

The Sanskrit word for ‘human’ is mānava, which literally means ‘Children of Manu’

A sketch showing the Great Flood

Matsya-avatara of Lord Vishnu pulls Manu's boat after having defeated the demon

The fish Matsya rescues the Saptarishi (Seven Sages) and Manu from the great Deluge

Matsya, Central India, 9th - 10th century. British Museum.^[8]

The earliest accounts of Matsya as a fish-saviour equates him with the Vedic deity Prajapati. The fish-savior later merges with the identity of Brahma in post-Vedic era, and still later as an avatar of Vishnu.The legends associated with Matsya expand, evolve and vary in Hindu texts. These legends have embedded symbolism, where a small fish with Manu's protection grows to become a big fish, and the fish saves earthly existence.

Etymology

Matsya is a Sanskrit word and means "fish". The term appears in the Rigveda.^[7] It is related to maccha, or meena which ancestor of matsya avatar which also means fish.

Vedic

Picture of Matsya Avatar- Fish incarnation of Lord Vishnu

The section 1.8.1 of the Shatapatha Brahmana (Yajur veda) is the earliest extant text to mention Matsya and the flood myth in Hinduism. It makes no mention of Vishnu, and instead identifies the fish with Prajapati-Brahma.The central characters of this legend are the fish (Matsya) and Manu. The character Manu is presented as the legislator and the ancestor king of meena's .

When the flood came, Manu used a rope to tie his boat to a large horn growing out of the fish. Pulling the ship through the rough waters.

the flood and rescue of boat By matsya (fish)

After thegreat flood, Manu became lonely because only he and the animals aboard the ship had survived. hen the flood receded, Manu, the sole human survivor, performed a sacrifice, pouring oblations of butter and sour milk into the waters. After a year there was born from the waters a woman who announced herself as “the daughter of Manu.”

Similarities to Babylonian Flood

1. The flood was brought by the god Ea and warned Utnapishtim
2. Both Manu and  Utnapishtim had to bring some of all living things onto the boat, plants and animals.
3. They both built the ships individually.
4. Both of their gods were afraid of the storm and fled when it came instead of staying. 
5.  Both myths had more than just 1 god

Similarities to Hebrew flood

1. Both ships ended up on a mountain.
2. Both Manu and Noah brought animals onto the boat.
3. Both were told/sent by gods in some form to build a boat.
4. They both had to build a ship based on faith of what their god(s) said.
5. Both Manu and Noah made a sacrifice once the water went away.

The Great Flood, by anonymous painter, The vom Rath bequest, Rijksmuseum

flood myth is real as it was mention in all religion

The Flood of Noah and Companions, by Léon Comerre, c. 1911. Oil on canvas. Fine Arts Museum of Nantes