So... is Shinryaku! Ika Musume finished or not?
NO, it is not finished.
Why?
The anime finished before the manga:
Anime finished: September 08, 2014
Manga finished: February 25, 2016
MangaUpdates contains information about the anime adaptation and indicates that it is incomplete.
Watching Order (by release date)
Here you have all the anime relations we detected ordered by release date, so you can see the reason for this status in context and also use it as watching order.
The mangas and the non-core contents are excluded by default, but you can enable them by clicking the buttons below:
Shinryaku! Ika Musume
The Squid Girl
Anime - Base
Release date: October 05, 2010
Shinryaku!? Ika Musume
The Squid Girl 2
Anime - Sequel
Release date: September 27, 2011
Shinryaku!! Ika Musume
The Squid Girl OVA
Anime - Sequel
Release date: August 08, 2012
Synopsis
Ika Musume, a squid girl from the depths of the ocean, rises to punish humanity for polluting the seas. Armed with her squiddy powers, she targets a beachside restaurant as her first step towards world domination.
However, her initial attempts at invasion fail miserably, and she ends up working as a waitress at the restaurant to pay off damages she caused.
The anime follows Ika Musume's daily life and adventures as she adjusts to life on land, makes new friends, and experiences human culture, all while occasionally pondering her original mission of conquest. It's a comedy about a squid girl learning to navigate the human world.