No Export for You: Averted: we've got the manga in North America, and other countries have it, the anime and sometimes the licensed games. The reason the English-speaking world hasn't got the anime is because TV wouldn't take it, not because of lack of trying on either side of the anime industry.
What Could Have Been: It was to be set in the pirate days, with Kaito as a pirate. The only heroic mermaids were Lucia (then named Lyre), Hanon and Rina. The villains were also merpeople and were only Izuuru, Gaito and Sara.