 If you liked
Aqua
|
 ...then you might like
Kabu no Isaki
|
It's a slice-of-life manga with heart-warming stories of a girl trying to be a licensed gondolier on a Venice-like city on Mars, and of the friends and adventures she has in this city. It also has many adventure and sci-fi elements in the story.
(There is also a sequel called Aria)