Fluke first appears with Princess Oona, Sven, Slim, Shelly, and Flip during a game of Capture the Conch, which he wins. He is juggling sea urchins when a ship Oona identifies as the Floating Palace appears at the surface, to Oona's delight. Oona tells him that the Floating Palace belongs to Princess Sofia, her human friend, and her family, the Royal Family of Enchancia, and swims off with Sven.
Oona and Sven later come back with Sofia, causing everyone to bombard her with questions. Fluke instantly becomes jealous of Sofia because of all the attention she's getting because of her magical abilities and the time she rescued Oona from a sea monster. When the Mer-Tones proposes to sing one of their songs as a thank you gift for throwing a party for everyone in Merroway Cove, he rudely dismisses it as a poor gift and tries to get a pearl out of a giant clam to upstage Sofia but gets himself stuck in the clam prompting Slim to swim off and get help.
Slim comes back with the other merkids and Sofia, who gets him out of the clam which he refuses to be grateful for and is uncaring that Flip's mantacorn horn was broken in the process. Still wanting to upstage Sofia, Fluke decides to get another horn from the mantacorn's cave, despite everyone telling him it's too dangerous. Sofia and Oona follow hm to the cave and try to get him to leave with them but the arrogant and jealous merboy refuses to listen in a way that wakes up the mantacorn, who chases and traps them. Fluke offers to show them out of the cave but a good and fed up Oona, who has had enough of Fluke's recent behavior and attitude, refuses stating "I'm not following you anywhere." Fluke retorts "I guess you'd rather follow the Princess. Go on Sofia. Lead the way. Be everyone's hero. Just like before." When Sofia asks that's why he tried to take the horn Fluke admits that he was jealous of Sofia for all the attention she was getting because of her heroics during her last visit. Oona tells Sofia "Lead the way, Sofia." in a way that tells Fluke she's very angry at him for his recklessness and disappointed that it was for such a petty reason. To make up for his behavior, Fluke gets one of the mantacorn's old horns and traps him in the seaweed patch. Afterward, they learn the mantacorn love music. He's later seen at the party Sofia's family threw for the colony.
Fluke's middle name is Clarence.
Fluke's the second merman to act antagonistic toward Sofia. The first was Plank.
Fluke is the third character to be jealous of Sofia, the first being her older sister, Amber, and the second being Jane.
Fluke is the first jealous character to be a male.