Miniaturization

Miniaturization is an additional Enchantix power introduced in Season 3.

Overview
In Season 3, Faragonda mentions the miniaturization power to the students of Alfea at her assembly in the quad. Later, it is revealed that when a fairy at the Enchantix level uses Fairy Dust to release all traces of darkness inside of her, she is able to miniaturize. Shrunken fairies also have the ability to enter dimensions where space and time flow differently. In Season 4, it is revealed that Believix fairies can also miniaturize.

Season 3
In "The Mirror of Truth," Faragonda holds an assembly in the quad concerning third-year students and their final exam; earning the Enchantix power. She mentions miniaturization as one of the additional powers to be unlocked for fairies who succeed in earning this new form.

In "The Crystal Labyrinth," the Winx arive at the door to the Golden Kingdom on their quest for the Water Stars and realize that in order to enter, they must miniaturize. With some explanation from Timmy as to why someone would need to remove impurities from their soul to miniaturize, the Winx release their Fairy Dust to find that everyone but Bloom has miniaturized. Bloom explains that since her Enchantix is incomplete, she cannot access all the tiers of the transformation. The shrunken members of the Winx enter the Golden Kingdom and successfully secure the Water Stars.

In "A New Beginning," the Winx, except Bloom, miniaturize in order to escape a crumbling Lake Roccaluce, making Bloom state her wish to have a complete Enchantix and be able to miniaturize as well.

Season 4
In "The Tree of Life," the Winx miniaturize in order to enter the houses in Pixie Village; this is Bloom's time using it and it gave her a bit of shock.

In "The White Circle," the Winx miniaturize in order to escape the Wizards of the Black Circle and enter the barn where Roxy is.

Season 8
In "The Wishing Star," the Winx miniaturize to get inside the Star Case.

In "Mission for the Prime Stars," Tecna mentions that the Enchantix power let the Winx enter a new dimension where space and time flow differently.

The Secret of the Lost Kingdom
The Winx were forced to use their miniaturization powers to gain access to the Tree of Portals so they could find a way of entering the realm of Obsidian. Only Bloom was incapable of entering because of her willed and therefore incomplete Enchantix.

Trivia

 * During the miniaturization process, the Winx dub themselves “Mini Winx.”
 * The power of miniaturization is similar to the shrinking ability of Tynix.
 * However, Tynix is able to shrink fairies down to a microscopic level whilst the miniaturization power shrinks fairies down to a relatively bigger size.