If you liked the Princess Mermaid manga, the Anime-Planet community thinks you'd like:
Cinderalla's happy life as a waitress at her father's restaurant is interrupted one day when the man suddenly dies. Luckily, he is reanimated as a zombie that very night, and life continues on as usual... at least, it would have, had the perpetually-hungry Caroline and her two zombie daughters not shown up and married Cinderalla's newly-undead relative! Now Cinderalla must cater to her demanding new family as well as fulfill her restaurant duties, much to her dismay. With the help of a rat and a fledgling fairy, can the overworked beauty break free from her oppressive stepfamily and find her own prince charming?
Princess Mermaid and Cinderalla are twisted tales loosely based on classic fairy tales. Since they're by the same mangaka, they both have gore, oodles of naked ladies, the same art style, and all sorts of bizarre plot points and characters.
Two poor brothers wearing matching bunny suits are distracted from their lives as street performers by a mysterious young girl and a very phallic train. After hitching a ride, they arrive in an elaborate underwater palace inhabited entirely by females, who "entertain" male guests from above the surface. Aside from the females, there is the Dragon God, and Hiroshi - the sole male member of the tribe who holds a deep-seated grudge about being forced to live in the air ducts! Is there any way for the brothers to return to their terrestrial life, after being swept up in this bizarre world of revenge schemes, court intrigue, and time travel?
Two very weird/quirky/surreal manga revolving around an underwater brothel run by an all-female (and all-related) group of mermaid/siren/fish-people-things. Loose re-telling of the Ryujin (water dragon god) legend.