Towelket: One More Time 3

The main character is a boy named Kachil - in the remake a female protagonist named Goko-chan can be chosen. With their sister Kimiru they are shrunken by the mysterious power of a magical book. At that time, the Kisechu, a group of tiny aliens bent on conquering the Earth, appear! The main character's allies must band together and defeat the six fish-hat leaders of the Kisechu to put a stop to their evil ambitions.