Etymology
Apparently coined around 2007 on a discussion thread on Seatails, a mermaid-enthusiast messageboard created by Kurt Cagle, who created a Wikipedia article on the cecaelia (originally “Cecælia”), inspired by Cilia (a cilophyte in “Cilia”, a seven-page short comic story published in issue #16 of the Vampirella comic magazine, released in March of 1972), cilophyte, Coleoidea, and the song “Cecilia” by Simon and Garfunkel, about a fickle and demanding lover (according to Cagle).