Not all communities of merman shun the company of men, intertwined against the common enemy..
Atlantis - the mythical Utopia - is the setting for the first Rhuna novel: Rhuna, Keeper of Wisdom http://www.amazon.com/Rhuna-Keeper-Wisdom-Historic-Fantasy/dp/1499005393/ref=tmm_pap_title_1
May 2015 (Issue 60) - This is very similar to the underwater city in Darkling Rise (Book 2)
This, my fellow humans, is the castle I rein on. My father is King Jubblee. I am his daughter. I have no siblings, but I have a pet octopus. I usually travel away from my kingdom, to explore other people, humans.