Lunessence's list "Merfolk Names" of 20 great name ideas: Okeanos - Yang!

Merfolk Names

Male and Female water-themed names from around the world and various mythologies. Perfect for island and ocean-themed inspiration.

Okeanos

A short, sweet name with plenty of substance, Ona is a multicultural choice, familiar in Spain, Lithuania, Egypt, and historically, in the US. Recent years have seen it reach the Catalonian Top 10 and the Spanish Top 100, while in the US, it hasn't appeared in the charts since the 1940s.
 
As a Lithuanian name, Ona is a variation of the classic Anna, giving it the meaning "grace", In this instance, it would be pronounced as o-NU (-U being like the u sound in up). 
 
From its Spanish and Catalan roots, it's both a short form of Mariona (itself a variation of Maria), and a word name, meaning "wave" in Catalan. Here, it would be said as O-nuh.
 
It can additionally be used as a short form of the Basque Andreona ("good lady"), and as a nickname for any Uzbek name with the element ona which means "mother" or "respected woman". Beyond that, it may be related to Iona, Winona, Simona, Onora, Verona, Alyona, and so on.

Mariona

Pelagius is a masculine name with ancient Greek and Latin roots, derived from "pelagos" meaning "sea" or "ocean." This rare name carries significant historical weight, most notably associated with the 5th-century British monk Pelagius, known for his theological positions that became controversial within early Christianity. The name also belonged to several early Christian saints and a 8th-century king of Asturias. Despite its historical significance, Pelagius remains extremely uncommon in modern usage. It has a scholarly, distinctive quality with its classical ending and connection to ancient languages. The name's maritime etymology suggests vastness and depth, while its historical associations connect to theological thought and early Christian history. For parents seeking a name with classical roots and historical significance, Pelagius offers a rarely-used option with substantial cultural depth.

Pelagius

This Roman name is featured in the New Testament as that of the governor of Judea.

Pontius

Pontus

Reidun

Saewine

Takumi

Tasi

Tengiz

Tiamat

Torunn

Mythological water spirit with the more common spelling of Ondine, heroine of an Edith Wharton novel. 

Merfolk Names

Okeanos

Ona

Mariona

Pelagius

Pontius

Pontus

Reidun

Saewine

Takumi

Tasi

Tasi

Tengiz

Tiamat

Torunn

Undine

Unni

Vaimiti

Yam

Yang

Yang