Ikachan

Near the bottom of an enormous abyss, there's only one way out. Swim in
a dark world under attack by frequent earthquakes and famine. This vast
undersea kingdom is filled with both dangerous and hamless denizens. Its
fearful inhabitants are led by a reluctant fish who has no answer to the
impending disasters.

Take to the sea and help your new friends flee their home and find a new
one. Their fate rests with you, Ikachan. You must help them find a way
out before it's too late. Use whatever tools you can and try to escape.
Swim, Ikachan, swim!