OonaXNonny

and Nonny are thought to be best friends. They both are quiet and think carefully before speaking. Nonny usually answers Oona's questions. It is possible they have crushes on each other.

In the theme song, Nonny introduces himself right after Oona. Later, they are seen dancing next to each other when all the Guppies are in a circle.

In A coulor just right, Nonny is seen dancing with Oona multiple times.
 * In the Outside song, Nonny is standing next to Oona.
 * In I Wanna eat in a restraunt, Nonny is seated at a table with Oona.
 * In Consruct with me, Nonny briefly looks over at Oona and he smiles.
 * In Sun bettifuil sun, Oona and Nonny are seen sitting together on an asteroid.
 * In Big Bubble City, Nonny and Oona are holding hands at one point of the song.
 * In The Police Cop-tetion! Nonny and Oona are in a team together. Later, they are shown crossing the street holding hands.