Selkie

The Selkies are small mermaid-like magical creatures that guard the portals connecting the Ocean of Andros to the oceans of all the worlds and realms of the entire magical dimension.they are known like as the underwater pixies. They have the ability to open or close the portals that link the Ocean of Andros to the oceans of another world or planet, and there is one gatekeeper for each world.

There are often many round creatures looking like baby fish that accompany them which turn onto brightly colored fish on coming in contact with magic or other fish. They are called bollabies.

History
The Selkies were first seen in The Spill during the crowning of Nereus, when Lemmy was holding the crown that King Neptune would place on Nereus' head.

After an oil spill occurred on Earth near Gardenia, oil from the spill traveled through the sea and reached the underwater portal linking the ocean of Earth to that of Andros. Phylla alerted by a Triton guarding vain and sealed the Earth portal after crossing it into Androswiththetritonguard.

There she and Lemmy saw Tritannus being mutated into a monster after absorbing the pollution and breaking free from the prison of Andros along with the Trix. With the help of the Trix and of the triton guards that he turned into monsters loyal to him, Tritannus stole the powers of the two gatekeepers. He then vowed to hunt down every Selkies and to steal all their powers, so that he would be able to enter the Infinite Ocean and from there conquer the whole Magic Dimension.

Six of the known Selkies bonded with the Winx Club. Eventually Tritannus absorbed all of the Selkies's powers granting him access to the Infinite Ocean.

Physical Appearance
The Selkies of the Oceans are miniature wingless mermaids with brightly colored skin. They wear hats that are brightly colored like them and which have decorations and a kind of veil on the back. They are colored like the respective planets which they guard.

Known Selkies

 * Lemmy (Andros) - Bonded to Aisha.
 * Phylla (Earth)
 * Illiris (Solaria) - Bonded to Stella.
 * Sonna (Melody) - Bonded to Musa.
 * Lithia (Zenith) - Bonded to Tecna.
 * Nissa (Magix)
 * Desiryee (Linphea) - Bonded to Flora.
 * Serena (Domino) - Bonded to Bloom.

Trivia

 * The Selkies have been rumored to be the underwater equivalents of the Pixies and will most likely replace them in season five due to the Pixies being busy starring on their Winx Club spin-off series, PopPixie.
 * The Selkies bear a certain resemblance to the Pixies and, due to their mermaid-like appearance and their small size, look like the Water Nymphs living in the Black Mud Swamp from Season 1.
 * A Selkie can detect whenever a fairy is nearby.
 * A Selkie knows her way around the ocean which she guards
 * A fairy bonds with the Selkie who guards the ocean gate to her respective home world, that also helps the Selkie to restore her power if it was taken from her.
 * A Selkie has the ability to break spells/curses placed on people.
 * The Selkies use the symbols on their foreheads as keys to open/close ocean gates and fight. Apparently, the Selkie's symbol resemble their bonded fairy's power, except for Nissa and Phylla.
 * When the Winx bonded with the Selkies one of the other Winx would say 'Their bonding'