Fluke and Rudder first appear when Marlin and Nemo accidentally wake them up from their nap on their rock. When the clownfish family ask them about the Institute, they tell them that it is a fish hospital. Their discussion is interrupted by the arrival of Gerald, whom they shoo off. The sea lions help the clownfish get in the Institute by calling their loon friend, Becky, to fly them in there. When Marlin mentions that he and Nemo need water, they trick Gerald into giving up his pail by inviting him on their rock before promptly kicking and shooing him off.
They next appear near the end as they watch the excitement of Dory saving her friends by vacating their rock (which is promptly taken over by Gerald) and despite not helping Dory, they are showered with fish (even being hit by a large one).
They last appear after the end credits where they are sleeping again on their rock, briefly shooing off Gerald again when he attempts to gain entry on the rock. They witness the Tank Gang being taken by the humans before resuming their nap, unknowingly being stalked by Gerald, who gives a devious laugh.
- In the early stages of the sequel, Idris Elba and Dominic West were originally going to portray the villainous Dr. Mobster and a shark hunter Jinx respectively, but they were scrapped and changed into sea lions instead.
- Andrew Stanton admitted that he casted Elba and West because he wanted to have a reunion between the two co-stars of The Wire.
- Fluke and Rudder's recurring lines: "Off! Off! Off!" when shooing away Gerald is similar to the Seagulls cawing, "Mine! Mine! Mine!" in Finding Nemo.
- Fluke is Idris Elba's third role for a Disney film released in 2016 (and the third of a talking animal role), the first two being Chief Bogo from Zootopia and Shere Khan from The Jungle Book.