- Oona was believed to be a vegetarian, but it was proven false in the episode "The Legend of Pinkfoot!". During Lunch she was having a turkey sandwich and in "The Lonely Rhino!", she had a cheeseburger.
- Like Nonny, Oona didn't sing a single dance song and only sings backup in most episodes, making her the girl who has sung the least amount of songs in the series. However, she had a line in Bunch of Bones (Reprise), and shared a duet with Deema in "The Puppy And The Ring", titled Flutter Guppies Realm Song.
- Oona's favorite color is pink, especially bright pink. Although, in "The Crayon Prix", she had to drive a canary yellow car.
- Oona is the only female guppy to wear a full tail, instead a half tail and bikini top
- Her best friend is Nonny, whom she is often seen with, when not with Deema. Deema is also one of Oona's very close friends. Deema often uses affectionate pet names for her on occasion also.
- Despite being in almost every Lunch segment,Oona rarely does the lunch jokes main punchline. The only episode which she did this was "Super Shrimptennial Celebration" (a horn on a cob).
- In "We Totally Rock!", it is revealed that Oona's favorite food is cream cheese and jelly sandwiches.
- Oona is the guppy to ask the most questions in almost every episode and Nonny usually answers her question.
- In the episode "Have a Cow!" it is revealed that Oona loves baby animals. It is also revealed in "Bubble Puppy!", "Check It Out!", and "The Oyster Bunny!"
- In some episodes during pop songs Oona sometimes plays the drums. Also in "We Totally Rock!" Oona plays drums in the story segment and in the concert.
- Oona has only been the main character in five episodes. ("Call a Clambulance!", "The Grumpfish Special!", "The Spring Chicken Is Coming", "Get Ready for School!", and "Swimtastic Check-Up!"), which makes her the guppy with the least number of times being the main character.
- In Construct With Me, in the third verse you can clearly hear Oona singing.
- Oona can be seen wearing a police officer costume in seven episodes. ("Super Shrimptennial Celebration!", "Can You Dig It?", "Happy Holidays, Mr. Grumpfish!", "The Police Cop-etition!", "The Amusement Parking Lot!", Super Guppies! and "Costume Boxing!").
- Oona's lunchbox is purple with a big pink star in the middle.
- In Season 3, she plays on the drums more often than before.
- For for some reason, her name is "Luna" in the European French Dub .
- On November 10, 2011. Bubble Guppies's Facebook asked the fans to answer "Which guppy is your kid most like?", and Oona is in third place with 63 votes.
- On January 24, 2012, Bubble Guppies' Facebook page asked the fans to answer "Which Bubble Guppies character would you name your kid after?", and Oona is in fifth place with 18 votes.
- Oona may be the youngest of the guppies.