Beatnik: Though not actually one, Grace seems to dress in a similar fashion
In "I Love the Nightlife", Kenny and Kat goes to a poetry club where a beatnik speaks while Kenny plays the bongos.
Big Brother Instinct/Papa Shark: Messing with Kat, especially if Kenny is present, is a bad idea. Case in point: in "Whaling on Kenny" which features Kenny's "friendship" with Buster the orca, Buster had spent the entire episode bullying the frankly terrified Kenny. When Kat shows up and Buster knocks her to the ground, Kenny flips and launches into a speech that's half Not Afraid of You Anymore and half "The Reason You Suck" Speech.
Big Eater: Kenny non stop. His eating habits become a problem for Kat's parents, as one episode was about finding a job to pay for his food bills. He and Kat settle for a mascot job for the local hockey team, where it turns out they aren't paid with money but with all the hot dogs he can eat. He's not fired for causing panic, but because he ate all of the hot dogs.
Disappeared Dad/Missing Mom: True to how sharks behave, Kenny never met his birth parents. It sometimes makes him depressed. And also the reason he became close to a baby shark he and Kat encountered in "Kenny the Dad".
Disco Dan: Peter loves the 70s', they were his "glory days". Grace hates that decade, and is glad they can't go the 70's party since Peter's disco suit got ruined by Kenny (which Peter thinks was caused by moths).
Does Not Like Shoes: Kat's parents wear sandals. Though Kat switches between sandals and shoes, but often wears sandals.
Everything's Even Worse With Sharks: Subverted. While Kenny does cause a bit of trouble, he usually has good intentions when causing it. Played straight with his hammerhead friend, Dan. Peter though believes this.
Completely averted in "Whaling on Kenny" where Kenny becomes the victim of Buster, an orca who is an absolutely viscous bully and not just to Kenny either; when Kat shows up after finding out what Buster's been doing to Kenny, he knocks her flat and she looks legitimately terrified about what he could do next until Kenny jumps between them to protect her.
Explain, Explain... Oh, Crap!: A variant. In "Whaling on Kenny", Kat has set up a friendship with Buster the orca for Kenny which, unknown to her, has lead Buster bullying Kenny badly; about halfway through the segment, Oscar finds her in the library where she's researching activities for the 2 to do together. After she offers to let him help, Oscar picks up one of her books, pages through it briefly and asks if Kat knew that orcas eat tiger sharks. Kat responds nonchalantly at first but then lets out a Big "WHAT?!" before grabbing the book to confirm the statement. She's...less than happy to find out what she's gotten Kenny into.
Granola Guy: Peter. In "Shark Shrunk", Kat believes it's to please his "hippie left-wing father".
Granola Girl: Kat arguably, since she decides to become a vegetarian like her dad.
Hulk Speak: Mulch the great white shark from "Mr. Popularity" speaks this way. Lampshaded by Kenny.
Mulch: Mulch eat kids!
Kenny: "Mulch eat kids. Mulch eat kids." Mulch has really gotta work on his vocabulary. Use your words!
Idiot Ball: Kat in "Whaling on Kenny". Kat had previously (since "Whaling on Kenny" was in Season 2) established as being a near expert on sharks, especially tiger sharks. Why was it a shocking revelation that orcas eat them?
In another episode, a pet trainer who repeatedly mistreated her students (especially Kenny) brought in a seal as a new pupil. When Kenny (who eats seals) naturally goes berserk, the trainer begins berating Kenny just in time to be caught by Kat who's disturbed by the treatment Kenny's receiving and appalled when she finds out about the seal, calling the trainer out on her stupidity. Fortunately the trainer is willing to listen.
I'm a Humanitarian: Averted, Kenny doesn't try to eat people. Certain circumstances come close to playing it straight, whether they get on his nerves or if they happen to smell like a seal.
Peter: Boy, for a fearless predator, he's pretty chicken.
Kenny: You're lucky I don't like the taste of balding vegetarians.
Interspecies Friendship: Kenny, a tiger shark, and Marty, a dachsund. Technically also Kenny's friendship with the human Kat.
Poor Communication Kills: In "Shark Shrunk", Kat tries to be a therapist to analyze Kenny; she deduces that he has a fear of abandonment and afraid no one likes him. However, Kenny misinterprets that nobody really doesn't like him.
Straw Vegetarian: After Kat decides to become a vegetarian, she tries to get Kenny to become one. But she eventually realizes she shouldn't force him to do something he doesn't want to (or in his case, can't) do.
Token Trio: The Phoebes: The blonde Caucasian, the African-American, and the Latina.
Too Dumb to Live: In "Mr. Popularity", the Phoebes bought a shark as a pet, after seeing a cute shark movie.
Trademark Favorite Food: As seals are the natural prey of tiger sharks, Kenny goes crazy trying to eat them. Fortunately, Kat is able to feed his craving with Seal Pops, Popsicles that are somehow FDA approved with seal meat. He also develops a love of Sushi.